Google is buying security firm Postini. Great for all the Google Office applications like Google Mail, but important for Google Talk. Based on Postini's product literature, they'll be able to quickly add inbound and outbound spam and virus filtering, content filtering (really big at education, finance and health care institutions), user blocking and activity/content logging. These are enterprise demands Skype only handles indirectly. The Postini acquisition doesn't solve GTalk's missing end-to-end encryption of IM, voice/video streams, and file transfers.