ASKanything
http://www.askanything.com/

"Get paid to share the knowledge"

This site offers lots of options on the kind of information exchange you want to do. Offer money or ask for free. Have the question/answer posted in public or kept private. Do you want email from answerers? Do you want answers in 30 minutes or several weeks?

Buyers post questions and offer a price. They pick a seller based on ratings earned and the prices they counterbid. The site emails the appropriate sellers and calls after the deadline to see if the buyer is satisfied or wants to notch up his offer. Sellers can keep track of the elaborate process with their own individual "my answers/counterbids" page.

You can browse the archives and see everything people chose to put on the site. But much of the negotiation and perhaps the final answer happens by email. Because they give so many options, it's interesting to see how the terms of the transaction affect the quality of the information.

The buyer must pay if the seller offered a counterbid and the buyer agreed. The buyer can demand royalties if he chose to put the question into the public database. The site holds the money and pays out, keeping a 20 per cent commission.