In reply to Jeff Chandler.

Yep, I've been utilizing that technique for quite a long time. This is actually how the main demo theme of Aesop is run.

The problem is with Facebook.

A lot of users have apps associated with their sites, which tracks sharing, etc, and that requires an App ID to be entered by the user.

That asynchronous code still needs to be in header/footer. Sure you could just use the straight sharing links, but that won't connect to your fb app.