lexipixel - 5:31 pm on Oct 11, 2013 (gmt 0)
Google to Use Your Data in Ads Via 'Shared Endorsements'
".....For those with a Google Account, a +1 you give or review you write might be used alongside an advertisement for the business you endorsed. "The +1 you gave your favorite local bakery could be included in an ad that the bakery runs through Google," the company said.
The ads have been dubbed shared endorsements, and will only be displayed to people in your social circle, or those with whom you've opted to share information like +1s and reviews. If you don't want Google using your information, you can opt out by navigating to the shared endorsement setting, unchecking the box at the bottom, and clicking "Save."
I beleive any web property that respects its users, if it has a feature that mines, shares or otherwise uses user data in any way would make that feature opt-in, not opt out.
Google, Facebook and other sites with large "free" user bases rely on the majority of people not bothering to read long winded policy change notices, and not wanting to waste the time to hunt don't the settings to opt-out.
...but, at least there is an opt-out setting.