They say having a workout buddy helps keep you motivated, and I think that's true. But is it too much to have all 400 of your Facebook friends as your motivational buddies?
If you're proud of running 3 miles in your fastest time yet, why wouldn't you post it and get all the positive feedback? Right!? But what happens when you slip up (because we all do) should you post that also? I bet if you do post it, you will still get positive feedback and suggestions on how to get back on track from your Facebook friends.
So what's the harm?