6. Postini
6. Postini
Price: $625 million
Announced: July 2007
FTC Approval: August 2007

Postini was one of the first partners with Google Apps and is now a core part of that area of Google's business. According to Google's Postini site, Google Postini provides security and archiving services to over 26 million users, and is a core part of its message security and discovery capability.

Four years since its purchase, Google decided this July to use Postini email security features in Gmail, which analysts touted as a major step in bolstering Google Apps security for enterprise. Don't be surprised to see more Postini integration into Google Apps and Gmail in the future.

Last updated August 16 2011: 12:14 PM ET
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