I decided to see how “Places” stacked up with Foursquare. I reactivated my Facebook account and reinstalled the iPhone app. Went to “Places” and clicked “Check In,” and… nothing. It mentioned something about turning on Location Services. I know I already have that enabled because other apps are using it without problem. Turns out you need to enable Location Services explicitly:

First, go to the Settings app and select General:

Select Location Services:

Make sure Facebook is enabled (On) if you want to use Places. If you want to disable Places, make sure this is set to Off.