Vertical search engines like Zillow.com (for real estate), and DentalProducts.net (for dentists) serve to deliver user results tied precisely to the category they're interested in -- often with more
relevance and expert sources than search on a big engine.
But Google's Custom Search Engine allows Webmasters to tap into its core search API and essentially create their own vertical
search engines -- moving beyond crawling and indexing information on their own site to give users results from relevant sites from all over the Web.
Read the whole story at Read/Write Web »