"It's the logo for Google's AdChoices system. Facebook will start using the system on most of its site ads very soon. If you see the logo on an ad, it means that you are seeing personalized ads based on your past browsing history.... instead of picking up bits and pieces from your browsing, AdChoices might just pull your Likes, groups and other information directly." Read the article for how to turn it off.
#PinterestNews Feb. 19th: We’re updating the Pin It button for Chrome to make it even easier for people to Pin things they find on the web. Now, when someone’s browsing your website, they’ll see a Pin It button any time they mouse over an image, so they can share it with their followers in a few clicks and quickly get back to browsing your site.