ing of ESTs that substantially alleviated, even if theydid not totally resolve, this threat to science fromoverbroad patent rights.

34. Directive 96/9/EC of the European Parliament and ofthe Council of 11 March 1996 on the Legal Protectionof Databases, 1996 O.J (L 77) 20.

35. For a critical commentary on the EU database directive

and kindred U.S. legislation, see, e.g., J. H. Reichman, P.Samuelson, Vanderbilt Law Rev. 50, 51 (1997).

36. See, e.g., National Research Council, Bits of Power:Issues in Global Access to Scientific Data (NationalAcademy of Sciences Press, Washington, DC, 1997)(expressing concern about European Unionstyle data-base protection).

37. The role of scientic organizations in facilitatingchanges in U.S. policy is recounted in (38).

38. P. Samuelson, Va. J. Intl. Law 37, 369 (1997).39. These efforts are recounted by J. H. Reichman and

P. F. Uhlir [Berkeley Technol. Law J. 14, 793 (1999)].40. I gratefully acknowledge research support from NSF

grant SEC-9979852.

V I E W P O I N T

Computer Networks As Social NetworksBarry Wellman

Computer networks are inherently social networks, linking people, orga-nizations, and knowledge. They are social institutions that should not bestudied in isolation but as integrated into everyday lives. The proliferationof computer networks has facilitated a deemphasis on group solidarities atwork and in the community and afforded a turn to networked societiesthat are loosely bounded and sparsely knit. The Internet increases peoplessocial capital, increasing contact with friends and relatives who live nearbyand far away. New tools must be developed to help people navigate andfind knowledge in complex, fragmented, networked societies.

Once upon a time, computers were notsocial beings. Most stood alone, be theymainframe, mini, or personal computer.Each person who used a computer sat alonein front of a keyboard and screen. To helppeople deal with their computers, the fieldof human-computer interaction (HCI) de-veloped, providing such things as moreaccessible interfaces and user-friendly soft-ware. But as the HCI name says, the modelwas person-computer.

Computers have increasingly reached outto each other. Starting in the 1960s, peoplebegan piggybacking on machine-machinedata transfers to send each other messages.Communication soon spilled over organiza-tional boundaries. The proliferation of elec-tronic mail (e-mail) in the 1980s and itsexpansion into the Internet in the 1990s(based on e-mail and the Web) have so tiedthings together that to many, being at a com-puter is synonymous with being connected tothe Internet.

As a result, HCI has become socialized.Much of the discussion at current HCI con-ferences is about how people use computersto relate to each other (1). Some participantsbuild groupware to support such interac-tions; others do ethnographic, laboratory, andsurvey studies to ascertain how people actu-ally relate to each other. This work has slowlymoved from the lone computer user to deal-ing with (i) how two people relate to eachother online, (ii) how small groups interact,and (iii) how large unbounded systems oper-atethe ultimate being the worldwide Inter-net, the largest and most fully connected so-

cial network of them all. Just one small por-tion of the InternetUsenet memberspar-ticipated in more than 80,000 topic-orientedcollective discussion groups in 2000. 8.1 mil-lion unique participants posted 151 millionmessages (24). This is more than three timesthe number identified on 27 January 1996 (5)

Computer scientists and developers havecome to realize that when computer systemsconnect people and organizations, they areinherently social. They are also coming torealize that the popular term groupware ismisleading, because computer networks prin-cipally support social networks, not groups.A group is only one special type of a socialnetwork; one that is heavily interconnectedand clearly bounded. Much social organiza-tion no longer fits the group model. Work,community, and domestic life have largelymoved from hierarchically arranged, denselyknit, bounded groups to social networks.

In networked societies, boundaries aremore permeable, interactions are with diverseothers, linkages switch between multiple net-works, and hierarchies are flatter and morerecursive (68). Hence, many people and or-ganizations communicate with others in waysthat ramify across group boundaries. Ratherthan relating to one group, they cycle throughinteractions with a variety of others, at workor in the community. Their work and com-munity networks are diffuse and sparselyknit, with vague overlapping social and spa-tial boundaries. Their computer-mediatedcommunication has become part of their ev-eryday lives, rather than being a separate setof relationships.

When computer-mediated communicationnetworks link people, institutions, and knowl-edge, they are computer-supported social net-works. Indeed, if Novell had not gotten there

first, computer scientists would be sayingnetware instead of groupware for sys-tems that enable people to interact with eachother online. Often computer networks andsocial networks work conjointly, with com-puter networks linking people in social net-works and with people bringing their offlinesituations to bear when they use computernetworks to interact.

The intersection of computer networkswith the emerging networked society has fos-tered several exciting developments. I reporthere on two developing areas: (i) communitynetworks on- and offline and (ii) knowledgeaccess.

Community Networks On- and OfflineCommunity, like computers, has become net-worked. Although community was once syn-onymous with densely knit, bounded neigh-borhood groups, it is now seen as a lessbounded social network of relationships thatprovide sociability support, information, anda sense of belonging. These communities arepartial (people cycle through interactionswith multiple sets of others) and ramifythrough space [a low proportion of commu-nity members in the developed world areneighbors (7)]. Where once people interacteddoor-to-door in villages (subject to publicsupport and social control), they now interacthousehold-to-household and person-to-per-son (9).

Although the support of collaborativework was the initial purpose of the Internet(both e-mail and the Web), it is an excellentmedium for supporting far-flung, intermit-tent, networked communities. E-mail tran-scends physical propinquity and mutualavailability; e-mail lists enable broadcasts tomultiple community members; attachmentsand Web sites allow documents, pictures, andvideos to be passed along; buddy lists andother awareness tools show who might beavailable for communication at any one time;and instant messaging means that simulta-neous communication can happen online aswell as face-to-face and by telephone.

Systematic research on what people ac-tually do on the Internet has lagged behindthe Internets development. After a long

Centre for Urban and Community Studies, Universityof Toronto, 455 Spadina Avenue, Toronto, CanadaM5S 2G8. E-mail: wellman@chass.utoronto.ca

www.sciencemag.org SCIENCE VOL 293 14 SEPTEMBER 2001 2031

C O M P U T E R S A N D S C I E N C E

period of pundit supposition, travelers tales,and laboratory studies of computer-mediatedcommunication, survey-based and ethnograph-ic research is now appearing.

These studies address a vigorous publicdebate about whether people can find com-munity online. Critics wonder whether rela-tionships between people who never see,smell, or hear each other can be the basis fortrue community [reviewed in (10); examplesinclude (1113)]. Other detractors make anopposite argument: The Internet may be soimmersive that it lures people away fromother pursuits (14) and involves them in on-line interactions that only reinforce their ex-isting opinions.

By contrast, enthusiasts see the Internetas extending and transforming community.John Perry Barlow asserts that with thedevelopment of the Internet . . . we are inthe middle of the most transforming tech-nological event since the capture of fire(15). They point to the ability of the Inter-net to span distances and time zones at lowcost, to sustain relationships based onshared interests (even when the participantsare residentially dispersed), and to providepowerful links between people and dis-persed knowledge (16).

Too often the debate has been (i)Manichean: The Internet is bringing heavenor hell, but nothing in between. (ii) Unidi-mensional: The Internet is such a powerfulforce that other considerations, such as gen-der and status in an organization, are ignored.(iii) Parochial: The Internet should be consid-ered as an entity in itself, rather than as fittinginto the full range of work, community, anddaily life. (iv) Presentist: The Internet is sucha transforming force that long-term socialtrends, such as the pre-Internet move to net-worked communities, are irrelevant.

As the debate continues, the Internet is

now used by a majority of North Ameri-cans, although its growth rate is slowingand may stabilize at about 60% of adults.The digital divide is decreasing rapidly inNorth America, although socioeconomicstatus (education, occupation, and income)remains an important differentiator (1720). The digital divide is much more sig-nificant in two ways in less developedcountries: (i) A much lower percentage ofthe population use the Internet and (ii) theusers are predominantly well-connectedelites (21). In the developed world, theamount of time spent online is increasing,per capita as well as overall. For example,the average AOL user spent 31 min per dayonline in the first quarter of 1997; in 4years, this had more than doubled to 64 minonline in the first quarter of 2001 (22). Nordoes familiarity breed interpersonal con-tempt: The more contact people have on-line, the greater the impression they makeon each other (23).

Survey-based evidence about the Inter-nets effect on community has been mixed.Most cross-sectional studies show that thosefrequently online are more involved in com-munity (2427). By contrast, one study (28)suggests that extensive online involvementtook people away from interaction withhousehold and community members. More-over, the only true longitudinal study foundthat some newbies became more depressed,alienated, and isolated during the first 6months of computer use (29).

Robust results indicating how the Internetfits into community life are now available(3032). It is becoming clear that the Internetis not destroying community but is resonatingwith and extending the types of networkedcommunity that have already become preva-lent in the developed Western world. Old tieswith relatives and former neighbors are main-

tained; new ties are developed among peoplesharing interests. It is not only that time andspace become less important in computer-mediated communication, but that it is easyto communicate with large groups of commu-nity members (using lists) and to bring un-connected community members into directcontact. The ease with which computer-me-diated communication connects friends offriends can also increase the density of inter-connections among clusters of network mem-bers within communities.

For one thing, as the newbies studied byKraut et al. (33) gained more experience withthe Internet, their depression and alienationdisappeared, and their social contact in-creased enough to have a positive impact ontheir overall interactions with communitymembers. A comparative analysis found thatsocial support obtained online helped peopleto deal with depression (34).

Other studies have found that the Internetincreased community interaction (35, 36).For example, a large National GeographicWeb survey found that face-to-face visits andphone calls were neither more numerous norfewer for people who use e-mail a great deal.E-mail just added to the fund of contact, sothat the overall volume of contacts withfriends and relatives through all media washigher for people who use e-mail a lot (27)(Table 1).

However, another study found that e-mailuse is displacing telephone use to some extent(37). Perhaps there are differences in thekinds of communication that take place onthe Internet or by telephone or face-to-face.Although one study of a dispersed workgroup found much similarity in what was saidby means of each of these media (26), anoth-er found that among community members,e-mail is preferred more when people want togarner information efficiently.

Table 1. E-mail use by total annual communication. [Source: Survey2000; see (27) for details]

E-mail useKin Friends

F2F* Phone Letters E-mail Total F2F Phone Letters E-mail Total

Within 50 kmNever 77 117 6 1 201 104 136 6 1 247Rarely 65 116 6 5 192 84 112 8 5 209Monthly 61 113 6 7 187 74 98 5 9 186Weekly 62 120 6 13 201 76 99 7 20 202Few times/week 63 115 7 24 209 83 113 7 37 240Daily 60 118 8 52 178 92 126 9 118 345Total 61 117 7 39 224 88 120 9 86 303

Beyond 50 kmNever 12 37 8 1 58 13 25 7 1 46Rarely 10 36 8 5 59 11 19 7 4 41Monthly 9 35 7 10 61 8 16 6 8 38Weekly 9 36 9 19 73 8 17 6 16 47Few times/week 10 39 9 35 93 9 19 7 30 65Daily 10 43 10 72 135 10 25 8 85 128Total 10 41 10 55 116 10 23 8 62 103

*F2F, face to face.

14 SEPTEMBER 2001 VOL 293 SCIENCE www.sciencemag.org2032

C O M P U T E R S A N D S C I E N C E

The positive impact of the Internet oncommunity ties is true for those living bothnearby and far away. The proportionate gainin contact is greatest for contact with friendsand relatives living at a distance (9, 38), asone might expect from a system able to crosstime zones at a single bound and in whichthere is no differentiation between short-dis-tance and long-distance messages. Yet onlineas well as offline contact is highest with thoseliving nearby (9, 38). Cyberspace does notvanquish the importance of physical space.For example, many e-mail and chat messagesarrange face-to-face meetings (26, 39).

The recent case of Netville (a suburb ofToronto) is especially interesting, becausehere neighborhood access to a high-speedInternet service helped bring neighborhoodmembers together for face-to-face get-togeth-ers, from visits in private homes to semi-public barbeques (40, 41). Those who werepart of the high-speed service knew threetimes as many neighbors as the unwired andvisited with 1.6 times as many. Nor was theInternet only used socially: Netville residentsused their local discussion list to mobilizeagainst the real estate developer and the localInternet service provider (40). To be sure,Netville may be a special case because theresidents were newly arrived and excited tobe part of an Internet experiment. Yet recentwork in Michigan (42) and Los Angeles (43)shows how the Internet can reinforce tradi-tional community development approaches.

Despite the past decades excitementabout the Internet, as it pervades life it maybecome as taken for granted as that once-transforming technology, the telephone (44).One indication is that those who have been onthe Internet the longest and the most fre-quently are least apt to feel that they are a partof an online community, although their over-all sense of community remains (27). Thismay reflect their greater likelihood of en-countering distasteful situations, such asflaming, hacking into accounts, virus trans-mission, or unwanted junk mail spam. Or itmay mean that those with much Internet ex-perience do not privilege it as a special formof community. Or it may support the fears ofthose who believe that computer-mediatedcommunication is not a satisfactory surrogatefor face-to-face contact.

Thus, preliminary findings create newquestions. At present, Internet studies ofcommunity are in full swing: The Pew Inter-net and American Life project does a monthlytracking study (35). The Stanford Institute forthe Quantitative Study of Society is doingfrequent surveys (14, 45). The U.S. GeneralSocial Survey, which is central to social sci-ence research, included an Internet module in2000 and may do so again. The 2001 Cana-dian General Social Survey has an Internetmodule. The large-scale international Nation-

al Geographic Survey2000 data are availablefor use [(27, 46); see http://survey2000.nationalgeographic.com]. The National Geo-graphic Society (in conjunction with Clem-son University and the University of Toronto)is doing an even larger and more comprehen-sive Web survey in fall 2001. A University ofMaryland Web institute is archiving manysurveys online with statistical software avail-able for reanalysis (47). Along with suchsurvey efforts, there is scope for ethnographiccommunity studies [such as what Hamptonand Wellman have done in Netville (38, 40,4749)].

Finding Knowledge in a NetworkedSocietyMany organizations are similar to networkedcommunities in having multiple sets of workteam members (including multiple superiors),physically dispersed relationships, and teamsof co-workers shifting by the day and week asemployees get involved in multiple projects.The situation is different from that dealt withby traditional organizational theory, whichcomprehends densely knit workgroups neatlystructured in bureaucratic, hierarchical orga-nizational trees (6, 5052).

How do people work together in large,sprawling, networked organizations wherethey are simultaneously members of multiple,transitory, physically dispersed teams? Inparticular, how do people in such organiza-tions obtain knowledge from others whenthey do not know whom to ask?

These questions are of immediate practi-cal importance for complex organizations.Hence, computer-supported solutions are de-veloping for working through trusted inter-personal relationships to identify, locate, andreceive information within and between com-munities and organizations. It is not surpris-ing that work in this area has been driven bycomputer scientists and communication sci-entists interested in building tools for knowl-edge access and management.

One issue is finding out who knows what;a more complex task in networked organiza-tions (53). Normally, one attempts to exam-ine the documentation or other help sourcesand then wanders out into a hallway in searchof friendly colleagues. The problem becomesacute, however, in distributed communities[(54), p. 97].

How do people wander the hallway whentheir team or other supports are physicallydistributed? One approach is to build aware-ness tools (55). Two of these, Cruiser (56)and Postcards/Telepresence (57, 58), provid-ed low-resolution video pictures of offices orcubicles. The picture told others whether peo-ple were in their offices and perhaps avail-able. The low resolution of the picture wasnot able to show what people were doing andafforded some privacy.

Another approach, Babble, builds on thetraditional groupware approach, which facil-itates a small defined group working together(59). Babble shows each person as an animat-ed and colored circle that moves closer to thecenter as the person gets more involved inteam activities.

When people are asked about the size oftheir networks, they consistently report themas smaller than the 1000 or more others thatthey probably know well enough to conversewith (6062). Rolodexes and their databaseequivalents are some help, but the listing canbe computer-supported. ContactMap (52)looks at ongoing Internet exchanges to recorda persons contacts.

Such memory aids typically record eachperson as a discrete entity. New develop-ments record the connections of networkmembers (63, 64). As such approaches de-velop, they have the potential to do primitiveautomated social network analysisidentify-ing clusters, boundaries, centrality, bridges,and blocksby analyzing who jointly re-ceives an e-mail and who forwards e-mails towhom.

Who holds the organizational or commu-nity memory, now that the veteran employ-eethe fount of work loreis neither knownnor accessible? Often people ask their work-mates. But what if they do not know? Peoplethen wonder whether friends of friends know,yet most people do not possess a list of all oftheir friends friends, much less are aware ofwhat their friends friends know. Yet it isreasonable to assume that the number offriends of friends is 100,000, assuming thateach person knows approximately 1000 oth-ers and that 10 percent of each persons tiesare unique. These are too many names tokeep track of, yet people often want a per-sonal touch when giving and getting informa-tion. They may want to talk to the informa-tion holder to supply a nuanced or confiden-tial request; the information holder may onlybe willing to release such information to afriend or a friend of a friend.

IKNOW is software that stores informa-tion about friends of friends; not only whothey are but what information they know(65). It seeks to answer the question: Whoknows who knows what? The hope is thatthrough the use of such indirect but personalties, people will supply reliable and appropri-ate information. Issues remain. The first isabout software that is scalable to map andsupply such contact information for a largeamorphous organization. The second is aboutdata collection: How do systems compile in-formation about who knows what? The thirdis about privacy: Do people want to revealtheir friends and their skill sets to strangers?

The Answer Garden (54) addresses suchissues of data collection and privacy, al-though it does not deal with interpersonal

www.sciencemag.org SCIENCE VOL 293 14 SEPTEMBER 2001 2033

C O M P U T E R S A N D S C I E N C E

connections. It provides tools for people tobuild repositories of commonly requestedquestions and answers, in part by building upthese repositories from ongoing question-and-answer sessions. Thus, only the informa-tion that has been publicly provided is avail-able. However, this provides only limitedaccess to the files of each work team member.Good solutions are not yet available that bal-ance team needs to have access to personalfiles with the needs of each person to limit ateams access to only the germane portions ofhis or her entire files.

With so much potential and need to con-nect, there is the need to prioritize communi-cation. Does my boss supersede my peers?Does my wife or husband have higher prior-ity than my sister or brother? Dealing withsuch matters would be an advanced imple-mentation for the simple filter rules nowcommonly available for e-mail. Important, asyet unpublished, work is being done to estab-lish rules for prioritizing computer-mediatedcontact, both deductively setting a priori rulesand inductively watching which messages aperson takes first.

An Internet year is like a dog year,changing approximately seven times fasterthan normal human time. Nevertheless, Iexpect the transition from a group-based toa networked society to continue (66 ).Although technology does not changesocietyit only affords possibilities forchangepowerful forces are shaping theInternet: increased broadband use, globalubiquity, portability, 24/7 availability, per-sonalization, and the switch from place-to-place to person-to-person connectivity.These suggest the accelerating need forsocial network concepts and tools for en-gaging with the Internet.

References and Notes1. The key HCI conferences are sponsored by the Asso-

ciation for Computing Machinery. They are SIGCHI(Special Interest Group on Computer-Human Inter-faces), SIGGROUP (groupware and group processes),and CSCW (Computer-Supported Cooperative Work).

2. M. A. Smith, personal communication.3. M. A. Smith, in Communities in Cyberspace, M. A.

Smith, P. Kollock, Eds. (Routledge, London, 1999), pp.195219.

4. M. Dodge, R. Kitchin, Mapping Cyberspace (Rout-ledge, London, 2001).

5. S. Southwick, Liszt: Searchable Directory of E-MailDiscussion Groups (report to BlueMarble InformationServices, Bloomington, IN, 1996).

6. B. Wellman, in Culture of the Internet, S. Kiesler, Ed.(Lawrence Erlbaum, Mahwah, NJ, 1997), pp. 179205.

7. B. Wellman, in Networks in the Global Village, B.Wellman, Ed. ( Westview Press, Boulder, CO, 1999),pp. 147.

8. M. Castells, The Rise of the Network Society (Black-well, Malden, MA, ed. 2, 2000).

9. B. Wellman, Int. J. Urban Reg. Res. 25, 227 (2001).10. B. Wellman, M. Gulia, in Networks in the Global

Village, B. Wellman, Ed. ( Westview Press, Boulder,CO, 1999), pp. 167194.

11. C. Stoll, Silicon Snake Oil: Second Thoughts on theInformation Highway (Doubleday, New York,1995).

12. M. Slouka, War of the Worlds: Cyberspace and theHigh-Tech Assault on Reality (Basic Books, New York,1995).

13. V. Jergens, Does the Internet Bring Us Down, NewYork Times, 3 September 1998 (online at www.nytimes.com).

14. N. Nie, Am. Behav. Sci., in press.15. J. P. Barlow, S. Birkets, K. Kelly, M. Slouka, Harpers

1995, 40 (August 1995).16. H. Rheingold, The Virtual Community (MIT Press,

Cambridge, MA, ed. 2, 2000).17. M. Kew, B. Wellman, Curr. Sociol., in press.18. A. Reddick, C. Boucher, M. Groseillers, The Dual Dig-

ital Divide: The Information Highway in Canada (Pub-lic Interest Advocacy Centre, Ottawa, Canada, 2000).

19. National Telecommunications and Information Ad-ministration (NTIA), Falling Through the Net (NTIA,Washington, DC, 2000).

20. E. Fong, B. Wellman, R. Wilkes, M. Kew, Correlates ofthe Digital Divide: Individual, Household and SpatialVariation (report to Ofce of Learning Technologies,Human Resources Development Canada, Ottawa,Ontario, June 2001).

21. W. Chen, J. Boase, B. Wellman, in The Internet inEveryday Life, B. Wellman, C. Haythornthwaite, Eds.(Blackwell, Oxford, in press).

22. A. Odlyzko, The History of Communications and itsImplications for the Internet (AT&T Labs-Research,Florham Park, NJ, 2000).

23. Y. Liu, The Effects of Frequency and Duration ofMessaging on Impression and Relational Developmentin Computer-Mediated Communication: An Explor-atory Study (report presented at the Annual Confer-ence of the International Communication Associa-tion, Washington, DC, 2001).

24. J. Katz, Wired 1997 68, 76, 274 (December 1997).25. J. Katz, R. Rice, P. Aspden, Am. Behav. Sci., in press.26. C. Haythornthwaite, B. Wellman, J. Am. Soc. Inf. Sci.

49, 1101 (1998).27. B. Wellman, A. Q. Haase, J. Witte, K. Hampton, Am.

Behav. Sci., in press.28. N. Nie, L. Erbing, Study Offers Early Look at How

Internet Is Changing Daily Life (Institute for theQuantitative Study of Social Science, Stanford, CA,2000).

29. R. Kraut et al., Am. Psychol. 53, 1017 (1998).30. P. DiMaggio, E. Hargittai, N. Russell, J. Robinson,

Annu. Rev. Sociol. 27, 207 (2001).31. C. Haythornthwaite, B. Wellman, Eds., special issue

on the Internet in everyday life, Am. Behav. Sci., inpress.

32. B. Wellman, C. Haythornthwaite, Eds., The Internet inEveryday Life (Blackwell, Oxford, in press).

33. R. Kraut et al., Internet Paradox Revisited (CarnegieMellon University, 2001).

34. R. LaRosa, M. S. Eastin, J. Gregg, J. Online Behav. 1(2001) (see www.behavior.net/job/v1n2/paradox.html).

35. P. Howard, L. Rainie, S. Jones, Am. Behav. Sci., in press.36. B. Anderson, K. Tracey, Am. Behav. Sci., in press.37. J. Dimmick, C. J. Gade, C. Rankin, A Niche of Microdi-

mension Analysis of Displacement of Long DistancePhone Use by E-Mail (paper presented at the Inter-national Communications Association Annual Meet-ing, Washington, DC, 2001).

38. K. Hampton, B. Wellman, Am. Behav. Sci., in press.39. R. Ling, B. Yttri, in Perpetual Contact, J. Katz, M.

Aakhus, Eds. (Cambridge Univ. Press, Cambridge, inpress).

40. K. Hampton, B. Wellman, City and Community, inpress.

41. K. Hampton, thesis, University of Toronto (2001).42. P. Resnick, Whos That? Connecting Neighbors

through Directories and Distribution Lists (paper pre-sented at CHI99 Conference, Seattle, WA, May1999).

43. S. J. Ball-Rokeach,Y.-C. Kim, S. Matei, Commun. Res.28, 429 (2001).

44. C. Fischer, America Calling: A Social History of theTelephone to 1940 (Univ. of California Press, Berke-ley, CA, 1992).

45. N. Nie, L. Erbing, Study Offers Early Look at HowInternet Is Changing Daily Life (Stanford University,2000; www.stanford.edu/groups/siqss/Press_release.html).

46. J. C. Witte, L. M. Amoroso, P. E. N. Howard, Social Sci.Comput. Rev. 18, 179 (2000).

47. The archive at www.webuse.umd.edu contains origi-nal data from more than 20 surveys in which behav-ioral questions about Internet usage were asked ofnationally representative samples, including the Dig-ital Divide surveys done by the U.S. Census Bureaufor the NTIA, the 2000 U.S. General Social Survey,and national time use surveys. Users can directlyanalyze the data interactively using statistical soft-ware. In addition to the data archive, the Web sitecontains an annotated bibliography of behavioral re-search into more than 15 areas of Internet use (suchas the digital divide, time displacement, and socialnetworks), articles on Internet behavior, and links toother resources.

48. B. Hampton, B. Wellman, Am. Behav. Sci. 43, 475(1999).

49. N. K. Baym, in Culture of the Internet, S. Kiesler, Ed.(Lawrence Erlbaum, Mahwah, NJ, 1997), pp. 103120.

50. N. S. Contractor, Manage. Commun. Q. 13, 154(1999).

51. N. Nazer, thesis, University of Toronto (2000).52. B. A. Nardi, S. Whittaker, H. Schwartz, First Monday 5,

30 (2000).53. R. Cross, S. Borgatti, The Ties that Share: Relational

Characteristics that Facilitate Knowledge Transfer andOrganizational Learning (working paper of the CarrollSchool of Management, Boston College, Boston, MA,2000).

54. M. Ackerman, D. McDonald, Answer Garden 2: Merg-ing Organizational Memory with Collaborative Help(paper 97-105 presented at the Conference on Com-puter-Supported Cooperative Work, Cambridge, MA,December 1996).

55. O. Liechti, SIGGROUP Bull. 21, 3 (2000).56. R. Fish, R. Kraut, R. Root, R. Rice, Commun. ACM 36,

48 (1993).57. B. Buxton, Telepresence: Integrating Shared Task

and Person Spaces, in proceedings of Graphics In-terface 92, Vancouver, British Columbia, May1992.

58. G. Moore, in Video-Mediated Communication, K. Finn,A. J. Sellen, S. Wilbur, Eds. (Lawrence Erlbaum, Mah-wah, NJ, 1997), pp. 301321.

59. E. Bradner, W. Kellogg, T. Erickson, Social Affordancesof BABBLE (paper presented at the European Com-puter-Supported Cooperative Work Conference,Copenhagen, Denmark, November 1998).

60. J. Boissevain, Friends of Friends: Networks, Manipula-tors, and Coalitions (Blackwell, Oxford, 1974).

61. M. Kochen, Ed. The Small World (Ablex, Norwood, NJ,1989).

62. D. J. Watts, Small Worlds (Princeton Univ. Press,Princeton, NJ, 1999).

63. W. Sack, Mapping Conversations: Position Paper forthe CSCW Workshop Dealing with Community Data[paper presented at the Computer-Supported Coop-erative Work Conference (CSCW 2000), Philadelphia,PA, December, 2000].

64. Q. Jones, G. Ravid, S. Rafaeli, Information Overloadand Virtual Public Discourse Boundaries (paper pre-sented at CSCW 2000, Philadelphia, PA, December,2000).

65. N. Contractor, D. Zink, M. Chan, in Community Com-puting and Support Systems, Lecture Notes in Com-puter Science, T. Ishida, Ed. (Springer-Verlag, Berlin,1998), pp. 201217.

66. M. Castells, The Rise of the Network Society (Black-well, Malden, MA, ed. 2, 2000).

67. Research underlying this article has been supportedby the Bell University Laboratories, Communicationsand Information Technology Ontario, Mitel Net-works, the Ofce of Learning Technologies (HumanResources and Development Canada), the Social Sci-ence and Humanities Research Council of Canada,and at the University of Toronto: our NetLab at theCentre for Urban and Community Studies, Depart-ment of Sociology, and the Knowledge Media DesignInstitute. Discussions with NetLab colleagues havebeen invaluable, especially J. Boase, W. Chen, K.Hampton, C. Haythornthwait, A. Q. Haase, J. Salaff,and B. Wellman. M. Prijatelj and U. Quach providedvaluable assistance.

14 SEPTEMBER 2001 VOL 293 SCIENCE www.sciencemag.org2034

C O M P U T E R S A N D S C I E N C E