When they launched places, the explicitly copied Foursquare and the check-in model. Zuckerberg named dropped Foursquare at the unveiling of Places.

They are now getting rid of Places. From the Foursquare blog post:

"As a part of this, we are phasing out the mobile-only Places feature. Settings associated with it are also being phased out or removed. (You can read more about how location works and settings affected here: http://www.facebook.com/about/location)

Yes, location will still be part of Facebook, as noted by Betabeat. But it will not be executed with the "check-in" model foursquare pioneered. The new way will be closer to tagging a user in a Google+ conversation.