On the Central Role of Mailing Lists: An Exploratory Study

Emad ShiahbNicolas Bettenburg

Bram AdamsAhmed E. Hassan

The Central Role of Mailing Lists

Open Source developers are distributed ….

... they communicate through mailing lists

… this makes mailing lists a rich data source that we can leverage

The Central Role of Mailing Lists

What we Studied…

DevelopersExternalFactors

SourceCode

Q4. Competition?Q1. Communicationstyle?

Q2. Stability?

Q3. Code changes vs.Mailing list activity?

Mailing Lists Studied

Case study using 22 different GNOME projects

Participant Message Contribution

Question 1

40%

60%

Participant Message Contribution

Divided participants into 2 groups:

Dominant group(Top 10% contributors)

Casual group(The rest of contributors)

2%

82%

16%

Distribution of Participation in Threads

Dominant only

Dominant and Casual

Casual only

Participant Message Contribution

Question 1

Answer 1

Stability of Participants

Question 2

Stability of Dominant Group is Important!

2%

82%

16%Dominant Only

Dominant and Casual

Casual Only

Dominant group are involved in 98% of threads

Stability of Participants

Cosine Distance (CD) to measure participant stability over time

CD = 1 0 < CD < 1 CD = 0

Stability of Participants

Cosine Distance

Casual

Time

DominantAvg. = 0.69

Avg. = 0.15

0

Stability of Participants

Question 2

Answer 2

Mailing List and Source Code Activity

Question 3

Mailing List and Source Code Activity

Code Activity (CA) = Lines added + Lines Deleted + Lines modified

Mailing List Activity = No. of messages posted

Mailing List and Source Code Activity

76.0

Type of Source Code Change and Mailing List Activity

Divide the code changes into the 3 categories:1. Additions2. Removes3. Modifications

… and measure correlation with Mailing List activity ….

Type of Source Code Change and Mailing List Activity

Associate words to type of Code changes

“new features”“feature request”

Additions

“bug”“patch”

“testing”“maintain”

Modifications

Type of Source Code Change and Mailing List Activity

Additions terms mentioned 57% time more in Evolution compared to Nautilus

Modifications terms were mentioned in 75% more messages in Nautilus compared to Evolution

Consistent

Mailing List and Source Code Activity

Question 3

Answer 3

Effect of External Factors on Mailing List Activity

Question 4

Effect of External Factors on Mailing List Activity

Effect of External Factors on Mailing List Activity

Quantitative study: measure the occurrence of competing mailing clients to Evolution

Effect of External Factors on Mailing List Activity

Qualitative study: study mailing lists content

Effect of External Factors on Mailing List Activity

Question 4

Answer 4

The Central Role of Mailing Lists