Um, I'm pretty sure the ads have always been there, just as an overlay. Now they're on the bottom. Who at AI (didn't) research this for the article?
Yep, I'm right, it's an update to their old way of displaying:
Edit to add: http://9to5google.com/2013/08/08/google-introduces-new-local-ads-experience-in-google-maps-on-ios-android/