How can I reward contribution?

I noticed today the opportunity to gain a single point on a Q&A. I am trying to get a Knowledge Management forum going. So far, we have seven communities within a small area of the organisation with discussion forums and areas in which to post documents of interest, events, etc. The use of this facility is not as active as I would like. If anyone has any ideas to increase contribution, I would be most grateful. As this is an opinion based question, I am happy to give the first 20 sensible suggestions the 150 points offered.