But, Google is still an ad company based on search.

FORBES: Why Google Is Doomed With Sudden Shift To Mobile

Categories are based on actual Google.com search terms and are matched up against your keywords, ad text, and landing page text.

FORBES: Google Wants You to Suck Less at AdWords

Programmable Web, a site that tracks mashups, figures that about half of the mashups it sees are based on Google's map business and about half of all mashups fund themselves using the Google ad machine.

FORBES: Magazine Article