I spent time working at Philz Coffee yesterday (now in downtown Palo Alto - and if you haven't enjoyed Philz... hurry. It's amazing coffee). They provide free wifi and do something really simple and smart... and surprisingly unique. When you access the free wifi, you are prompted with a screen to acccept them terms & conditions. This is very normal:

When you accept the terms, most companies redirect to you an ad or content hub of some sort (here is an example from Starbucks).

Philz redirects you to their Facebook fan page. Simple. Clever. You are in Philz already... why not like their page? Why not check in? Post a picture of your coffee?

Why doesn't everyone do this? It is clearly a better return than some CPM ad that users are dying to get away from... it's relevant, not spammy and surprisingly welcome.