Of all the major corporations Facebook could have hooked up with to create an app for their new its location-based services, I would not have guessed it would be McDonald's. Two reasons:
The first is that I don't know too many people who'd want to check in at a fast food chain. Broadcasting that you're proud, excited, or just plain happy to be at McDonald's is like broadcasting you have bad taste in fast food (is there no Chick-fil-A in your life?), you're excited about clogged arteries, or you're looking for love in all the wrong places.
The second is that McDonald's, while very popular still, is not exactly hip. I realize that Facebook now has more older folks than college students these days, but updating your location seems less like something a Baby Boomer would be up to.
This is why I'm not yet warning the folks at FourSquare to watch out! as I'm unsure they have anything to worry about just yet. Heck, Yelp has been allowing users who have their iPhone app to check in to places for a while (by the way, Yelp team, where's this functionality for Android, hmm? I've been waiting). Yes, Yelp has far fewer users than Facebook, but it makes a lot more sense to check in from Yelp than from Facebook. At a McDonald's.
It'll be interesting to see what happens when the app goes live. Will Facebook users flock to McDonald's more now that they can announce it to their friends while also posting a picture of an Angus Third Pounder to their profiles? Or will this be the world's most effective diet plan as Facebookers stay away from the golden arches so as not to alert people to their midnight Big Mac runs?