SEO by the Sea has a really interesting post detailing all of Google’s acquisitions since 2001. Unfortunately, no amounts were given, but the author did go to the trouble of listing the relevant patents and abstracts where available. Here’s the list in a nutshell:
Android (August 2005), software for mobile telephones
Akwan Information Technologies (July 2005), an R&D center in Brazil
Dodgeball (May 2005), social-networking software for mobile devices
Urchin Software (March 2005), Web Analytics software (became Google Analytics in Q3 of this year; this is coincidentally the app I use on our webserver, and is easily the best in its class)
Zipdash (December 2004) Provides navigation assistance for road traffic on mobile in real time by GPS.
Where 2 Technologies (October 2004), Internet mapping
Keyhole (October 2004), imagery by satellite
Picasa (July 2004), software of management of photographs on line
Ignite Logic (May 2004), design of turn key legal sites
Genius Labs (October 2003), Biz Stone was Genius Labs
Sprinks (October 2003), paid advertising
Kaltix (September 2003), Research on personalized search, from Taher Haveliwala, Glen Jeh, and Sepandar Kamvar
Applied Semantics (April 2003), contextual advertising
Neotonic Software (April 2003), email customer support
Pyra Labs (February 2003), editor of Blogger, blogging platform
Outride (September 2001), a Xerox PARC spinoff, data-mining and semantic analysis
Deja.com (February 2001), Purchase of their usenet archive and other assets, which become Google Groups