It seems as though nothing short of a new buzzword can stop the burst of activity in the vertical search market, and who are we to complain? Vertical search engines differ from their horizontal brethren (who attempt to index the Web as a whole) by focusing on a single topic or niche about which to index information from the Web. Often, a VSE can deliver results with much greater relevancy and accuracy than major horizontal players like Google, Yahoo, and Microsoft.

There is more to be gained from vertical search than meets the eye. Vertical search engines give us a more complete look into domain knowledge and can help in the creation of domain-specific ontologies, especially those domains that require dedicated and qualified domain experts to construct, which is usually both difficult and expensive. Therefore, we can look at vertical search engines as rich silos of domain knowledge that can be leveraged to produce domain-specific ontologies that would otherwise be too costly to develop or would require expertise in a field inaccessible by current resources.

Doesn't that sound like a lot of fun? It does to me. Dozens of new vertical search engines (and aggregators of their kind) appear each month to feed our insatiable appetite for relevant, fresh information. It will be interesting to see how the horizontal search players address the issue of relevancy and accuracy within specific domains, as well as how vertical search will impact the development of domain-specific ontologies, natural language processing, and of course the Semantic Web.