Ads are served to non-members; the guys that arrive into questions by searching for information on Google or whatever. If you log out and view this question, you’ll see ads at the top of the discussion section.
Fluther also has a commission account at Amazon. So if I suggested an item on Amazon.com in response to something, and you followed the link and then bought it, Amazon knows that you arrived there from Fluther.
Fluther receives a small percentage of the profit from the sale. It doesn’t cost you anymore though; it’s just Amazon saying thanks to Fluther for referring you to them.
The third revenue stream is from the Fluther shirts sold at Insanely Great tees. Buy yours today!
The final revenue stream is from selling the organs of people that have over-Fluthered and slipped into a coma. Felt sleepy yesterday? Missing a kidney? Now you know why.
I don’t think there’s anything else, but I’m not sure. Andrew isn’t on iChat right now so I can’t ask.