It is a good idea to incorporate bitcoins into. I see two possible scenarios: Users who have bitcoins can tip people who give good answers, or you could have advertising to build up some revenue, and then give a reward to the winning answer from the company account, using bitcoins to make the payments. Or you could do both, with people having an option to tip answers, but also have a reward for the winning answer.
Either way, it would take a large marketing push to get people using it, people will not want to ask questions somewhere where nobody is there to answer yet. If done right, this could be marketed to non-bitcoiners, and then if they want to withdraw money they earn by answering questions they have to use bitcoins. Alternately, they could use the credits to tip other people who answer. You could pair it with a nice webwallet service to get them using bitcoins and help them understand what to do with them. I like strongcoin because of the security, but BTCinch is probably easier to understand for bitcoin newbies.
Fantastic idea both on the tipping and the advertising. People would sit on that site waiting for an question to be asked in hope that they provide the most helpful answer to the question in hopes of someone tipping. Great idea!