What is an ontology? In case you're disinclined to follow the link, I've quoted Wikipedia's excellent article on the subject:


SWOOP, pictured at right is an ontology based browser that can be downloaded for free. It's an excellent tool to play around with in order to get a good idea of what ontologies are, particularly in relation to web pages. The importance of ontologies is their use by search engines to help disambiguate queries, find more relevant information and identify websites that are well structured for the delivery of hierarchical information.

For example, if you were to construct a website about French cuisine, you would want to seperate the information into categories, possibly by region, ingredients, meals, etc. The ontologies for the seperate pages would help a search engine to "learn" what content was contained in the pages and assist them in identifying that content that would be most relevant given a complex search string, like "bordeaux regional french cuisine".

For most SEOs, ontologies have not been an important subject because;

1. Search engines have failed to implement them effectively
2. Most of the phrases SEOs target are short, general queries
3. Most users are not yet searching with this level of complexity or detail

However, in being prepared for the future, it is important for SEOs and webmasters to recognize the great value in writing for an ontology based web scheme. Not surprisingly, this makes for fantastically easy-to-use and readable sites and pages. I'm personally looking forward to creating my first (from scratch) site architecture based around the principles of ontologies and hierarchies over the next 2-3 months. I'll let you know how it goes!