A year ago today I wrote, in the comments to 'Things Google Knows About You', that the one piece of personal data other companies had access to that Google didn't was IM logs.
From the privacy section (emphasis mine)...
We will never share personal information with unrelated third parties for marketing purposes without your express permission.
Google Talk does not archive the contents of your text or voice communications on Google's servers.
Google employees do not access the content of any instant messages, voice transmissions, or files you send or receive.
Google only shares personal information with other companies or individuals outside of Google in the following limited circumstances: [...] We have a good faith belief that access, use, preservation or disclosure of such information is reasonably necessary to (a) satisfy any applicable law, regulation, legal process or governmental request, (b) enforce applicable Terms of Use, including investigation of potential violations thereof, (c) detect, prevent, or otherwise address fraud, security or technical issues, or (d) protect against imminent harm to the rights, property or safety of Google, its users or the public as required or permitted by law.
We may record information about your usage of Google Talk, such as [...] the contacts you communicate with.
Personal information collected by Google may be stored and processed in the United States or any other country in which Google Inc. or its agents maintain facilities.
When Google Talk uses OTR encryption for all messages by default, I'll take this back (I can see that they could still claim incompatibility with other clients at the moment).
All they need now is location, but that shouldn't take long to triangulate: "Google is making it easier for anyone in the U.S. with access to a mobile phone to sign up for a Gmail account. When users visit http://gmail.com and enter their mobile phone number, they will receive an invitation code via a text message."