We use question answer plugin in our forum.
Till now we have a very successful experience with it (Thanks for making it)
Recently we we been thinking about cancelling the google AdSense from our website and go with donation to maintain our service, so with this thought we came with this idea that when someone one gets the solution by marking the answer (as solution) gets the message encourage him/her to make a small donation as appreciation to the team solved the problem.
This function can be turned on and off according to our needs.
So what you guys think ?