Latent Semantic Indexing (LSI) And SEO

Indexing has always been considered a highly targeted science. Enter a search query into Google search and the pages that are displayed are generally optimized towards that exact word or term. However, in their continual battle to server the most relevant but most natural pages with genuinely useful information Google has injected latent semantic indexing (LSI) into its algorithms.

What Is LSI?

LSI is a unique indexing method that potentially takes Google search one step closer to becoming human in its way of thinking. If we were to manually search through web pages to find information related to a given search term we would be likely to generate our own results based on the theme of the site, rather than whether a word exists or does not exist on the page.

Why Search Engines Might Adopt Latent Semantic Indexing

The extremely rigid form of "keyword indexing" also meant that black hat SEO techniques were easier to implement. Search engines could be manipulated into ranking a site highly by using set formula. Originally, cramming a page with a particular keyword or set of keywords meant a site would rank highly for that search term. The proceeding set of algorithms ensured that your link profile played more of an important part than your keyword density. Reciprocal linking soon followed once again making it possible to manipulate the search engine spiders by exchanging links with tens, hundreds, or thousands of websites.

Reciprocal linking was soon beaten as Google and to a lesser extent Yahoo and MSN save less credence to a reciprocal link as they did to a one-way inbound link. Latent Semantic Indexing is another, particularly powerful, method to try and make their result pages appear more natural with natural pages filled with natural content.

The Effects

The introduction of LSI has seen some dramatic changes in the search engine result pages already. Sites that had previously performed well because of an impressive link profile based on a single keyword have found their pages slip in the rankings. Other pages with a more diverse portfolio of inbound links are taking the lead with search terms for which they had not previously performed.

SEO is far from dead because of LSI, in fact if anything, it has probably increased the need for professional white-hat SEO on your website. The field of SEO, though, has almost certainly changed. Website content copywriting for Google's benefit is not solely made up of keyword density and keyword placement as it once was and link-building techniques will need to change to incorporate LSI algorithms but it can be done.

Writing Content For LSI

If optimizing solely for Google then a web page can, theoretically, be naturally written and naturally worded. When we write we instinctively include the appropriate keyword in our text. In order to avoid repetition (or keyword optimization, as it was once called) we would often alter some instances of these keywords for other words with the same or very similar meaning. We naturally include the …