How Google Uses Latent Semantic Indexing

Most people who have used the Internet, or even know
what it is know what Google is. But most people don’t
know what exactly it is that Google does.

Or rather what makes Google do what it does. Google
searches are able to be so accurate because of Latent
Semantic Indexing.

Latent Semantic Indexing allows a search engine to
determine what a page is about by searching for one or
more keywords selected by the user.

It adds an important step to the document index
process. LSI records keywords that a document contains
as well as examines the document collection as a
whole.

By placing importance on related words, or words in
similar positions, LSA has a net effect of making the
value of pages lower so they only match specific
terms.

Search engines such as Google try to figure out phrase
relationships when they are processing keyword
queries, which in turn improve the rankings of pages
with related phrases.

This happens even when those pages are not focused on
the target theme. Some pages are too focused on one
phrase and they tend to rank worse than you would
expect them to.

In fact, some are even filtered out for being too over
optimized. Pages that are focused on a wider net of
related keywords tend to have more stable rankings.

Although the LSI algorithm doesn’t understand anything
about what the words mean, the patterns it notices
make the search engine look extremely intelligent.