How do you know when someone isn't on Facebook? ;)

Is there a site to sign up on so people can find you and find out that you are not on facebook? That would be great! Maybe facebook could integrate those results into there people search. "John Smith, Anytown, USA isn't on facebook. Try emailing him".

Well joke's on us because they could already do this. The Facebook knows about my existence. It knows my name, my face, and my friends. My email too. I'd have to avoid contact with all people that use the Facebook to prevent this. Infeasible.

They just don't publish the data because they have little to gain from it and there's no reason to needlessly antagonize people. They sell it without telling anybody.

I think most people on Facebook are that way because they don't want to be reached. That would be a tough sell to us privacy-conscious people.

... They'll tell you.