It would be nice to give thanks to those who helped solve or troubleshoot problems. That might help motivate users to respond so that they can get some recognition. It fills the esteem need on Maslow's Hierarchy of Needs.
Thanks CaptSilver! It's a good suggestion, although nothing beats a personal "thank you" message posted in response to something. A counter just feels... cold. Lacks the human touch. Still, it's better than no thanks at all!