A site like Facebook ought to a be a paradise for advertisers. All those people! All that data! How could anyone fail to strike marketing gold with such a powerful medium at the their disposal? A lot of folks, actually– it turns out that finding a way to take advantage of the site’s social media properties while still respecting the terms of service can be a little tricky. Several ad agencies say they’ve run afoul of the site’s privacy policy. Two big takeaways here, experts say: engagement beats data mining any day and if you’re thinking about doing something even vaguely fishy with a network’s TOS, knock it off. The customer outrage you’re risking just isn’t worth it. To find all kinds of tricks that do work, try signing up for SmartBrief on Social Media‘s daily newsletter.