You can see a summary on https://www.eff.org/deeplinks/2012/02/what-actually-changed-...
As the EFF mentions, this was a big privacy policy change, and it was widely announced. For example, I searched through my emails right now and found an email from Google (on my @gmail.com address) on 2012-01-28 announcing the change and asking me to "please take a few minutes to read our updated Privacy Policy and Terms of Service at http://www.google.com/policies".
For completeness sake, the diff from the changes on June 28th: https://www.google.de/intl/en/policies/privacy/archive/20160...
Disclaimer: I work at Google, but not on anything related to this. I speak for myself, not for the company.
EDIT: Interestingly, the language in the 2012 unified privacy policy matches very closely the language that was used in Google Voice's privacy policy since 2009: https://web.archive.org/web/20090315193708/https://www.googl...
> Google's servers also automatically collect telephony log information (including calling-party number, forwarding numbers, time and date of calls, duration of calls, SMS routing information, and types of calls).