A great blog on motivation by Rex Lee: see http://rexsthoughtspot.blogspot.com/2009/10/maximizing-business-value-from.html He talks about how we introduce social computing to an enterprise.
The idea of "if we build it they will come" will not work. He points out the very low participation of people who make additions so Wikipedia, 1%.
We need to make it fun and a challenge that makes people want to participate. I participate in Facebook because I find it fun and am able to keep in touch with lots of people easily.
So for the enterprise how do we make it a fun and rewarding activity?
I welcome comments and suggestions.