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Latent Semantic Analysis & Indexing
By
Mercy Livingstone.
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What is latent semantic indexing?
Origin of LSI
LSI and Search Engines
Why LSI introduced into Natural Search Result
LSA – Latent Semantic Analysis
LSA with an Example
Why LSI important to your SEO activities?
Implementing LSI in your website
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What is latent semantic indexing?
Latent Semantic Indexing helps to retrieve accurate information from the very large data base.
Invented for information Retrieval in Late 1980’s
The contexts in which certain word exists or does not exits determine the similarity of the document.
Closely models humans learning, especially the manner in which people learn a language and acquire a vocabulary.
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Origin of LSI
LSI invented to help in digital libraries such as in varsities to get the exact information.
Example,
Students looking for a tutorial may not find a e-book under same theme since that is a different phrase even though the e-book have required content. (E-book, Manual, Tips, Tutorial, Guide)
LSI in SE Language: Latent semantic indexing allows a search engine to determine what a page is about outside of specifically matching search query text.
LSI gives the search engines the ability to provide its users a more relevant list of options to choose from
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LSI and Search Engines
One of the ways LSI has changed the way Search Engines’ looks at sites is a shift from "keyword" to "themes".
Initially, search engines would look solely for the presence and frequency of keywords on a webpage to determine relevancy >> Poor Results
Humans are not looking for pages that contain specific keywords, they are looking for sites build around a theme.
Ex, New Wind Turbine, New Wind Turbine House Installation
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LSI and Search Engines (Cont…)
Applied Semantics >> http://www.appliedsemantics.com/
Applied Semantics created this concept to find relevant content to display advertisements. Google acquired them in 2003 April to use this concept in Google Adsense.
Google first used this in ad sense to display relevant ads.
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Why LSI Introduced in Natural Search Results
A conventional search engine that bases its results on 'keyword only' analysis may not give the best results. This is because the older search engine programs cannot tell the difference between:
Similar words with different meanings. e.g.: Dice - Die (dice plural) - Die (as in dead) - Die (as in mould) or Router (wood shaper) - Router (internet connectivity)
Words that are similar in meaning but spelled differently, e.g. : sickness - vomiting
Singular and plural forms of words, ex: dice/die, dog/doggies,
Words with similar roots, such as ‘Education' ‘Educational,'
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LSA – Latent Semantic Analysis
Compares Words in a Paragraph
Compare the paragraph with the rest of the Page
Compares the page with the rest of pages in the website
Make a decision on the theme of the Website
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LSA With Example
Dog
Puppy, Fat Puppy
Puppy breeding tips, Dog Training
Website Theme > Dog
Health, Child
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Why LSI important to your SEO activities?
Search engines such as Google do try to figure out phrase relationships when processing queries, improving the rankings of pages with related phrases.
Ex, Tiger Woods, Education, White House
Pages that are too focused on one phrase tend to rank worse than one would expect (sometimes even being filtered out for what some SEOs call being over-optimized)
Pages that are focused on a wider net of related keywords tend to have more stable rankings
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Implementing LSI in your website:
Develop themed sites on a broad scale rather than centering around one keyword.
Instead of keyword stuffing or “keyword optimization”, strive for more naturally worded and written pages.
With regards to your keywords, try to include synonyms, related words, plurals, and various tenses whenever possible throughout your site.
Use, ~(keyword), will give you the related words.
When establishing inbound links, be sure that they do not all go to the same keyword; have inbound links go to a number of different keywords and relevant terms within your site.
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Do not bother seeking irrelevant reciprocal links.
Use variations of your keyword and synonyms. That makes it easier for search engines to determine the topic of your site.
LSI does exist, but not in the form that Google would have us believe, and not in any form that you can use to make your website ‘LSI compliant’
Implementing LSI in your website:
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Find Related Words
http://wordnet.princeton.edu/perl/webwn
http://www.gorank.com/seotools/ontology
http://thesaurus.reference.com