We have said it before, but Google is awesome.  The algorithm for determining search engine positions is very complex and very little is known about the composition of it.  We certainly know that links are important, as are headings; but to what extent weighting is given say for reciprocal versus one-way links, or heading one over heading 2, we simply don’t know.  A huge focus is always given to the Page Rank Index, which determines a pages’ importance relative to other pages based on the number and quality of incoming links.  However, increasingly I feel search engines are basing less emphasis on links and more indexing on semantics.  Microsoft’s recent acquisition of Power Play is proof in point - clearly they believe they way forward in search engine performance is in improving the Semantic Indexing.

When we talk about Semantic Indexing, one of the algorithms that I find interesting is one known as the Latent Semantic Indexing algorithm (LSI). LSI determines a websites importance for it’s keywords and keyword phrases based on the websites use, and composition, of other keywords that commonly appear alongside the chosen keyword and keyword phrases. In this way the Latent Semantic Index also considers the content of your website in evaluating the rank of a single web page by looking for compositions of words that are considered to be commonly associated with the keywords you have optimised your website for.

Optimising your website for Latent Semantic Indexing algorithms necessitates excellent design of your website structure and architecture. At the upmost importance is the proper use of keywords as part of your internal link anchor text that properly support your top-teir keywords.

The best way to optimise your website for Latent Semantic Indexing is to create what are known as thematic silos. This entails creating a top level page for your particular keywords and then creating pages under this page for related complementary keywords in the same theme. Looking at a practical example let’s say we have a hostel in Sydney - a silo focussing on Sydney might look like this:

One of the debated points in the concept of Semantic Indexing is the degree to which theme bleed can occur by providing links to other websites - or even to web pages with your own site but outside the structure of your theme silo. I am not certain about this argument however, as I believe that good outbound links to high quality resources add value to your website both from a usability and from a search engine point of view; and that solid inter-linking throughout your website is important.

One of the important points about optimising your website for Latent Semantic Indexing algorithms using a strict theme silo structure you will find that you are in fact optmising your website for “long-tail keywords” - that is keywords that have lower search volume, but are more specific - such as, “central train station, Sydney city hostel”. The idea of optimising for the Semantic Indexing is that the more long-tail keyword phrases you rank highly for, the better you will do in more competitive terms.

Tags: links, SEO

This entry was posted on Monday, August 11th, 2008 at 9:06 am and is filed under Opinion. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.