As a part of their search results search engines like Google and Yahoo employ the techniques of latent semantic indexing(LSI) which is extremely important for developing relevancy in ranking and building our lengthy list of search and nowadays also for universal search.
How we define LSI? Latent Semantic Indexing is a key component that how search engines take into consideration the background of web site content. Typically based on a concept of frequent occurrence and grouping of words and combination of documents based on the occurrence idea. In short terms search engines come to recognize what words will surround the other words. This practice is substantial in quite a few languages as it is typically widespread for words to have different meanings.