Last week Google started rolling out their new email suggestion feature - put in one recipient and they will make suggestions of others that you may want to include in the email being sent. While handy, this service shows that Google is collecting information from the emails - to make the suggestions they have to keep track of who you email.
Basically they only store associations of addresses included in sent emails and have yet to combine messaging sent between Google Groups and other similar groups. While the feature can be handy - three clicks instead of typing in names - my laziness should not promote potential privacy problems.
I am sure the police would love the feature.- can't wait for a TV show that catches the bad guy by using known Gmail associates. But I will be more impressed when I log in to Gmail and am told my email to friend was written and sent... and hey while we are at it Webmaster Tools and Google Analytics tells me something has changed my rankings and they start my Adwords spend.But with that information Google could tweak their algorithm to impact those most likely to spend more on PPC... nahhhh they wouldn't.