Yelp has acquired Turnstyle Analytics, a marketing company that tricks lures people into giving companies their email addresses when they login to their free wifi network, for $20m.

With this acquisition, Yelp can offer businesses the ability to track when users visit their stores and send them loyalty rewards for repeat trips. And as much as we all hate promotional emails, that sweet, sweet internet hookup is hard to resist… especially if you’re at the end of your data cycle.