Thanks Abe1 for this hack. I installed this the other day and everyone loves it. I changed things up a little bit and made it so when user click the thanks or groan it keeps a running total (+3 or -1, that type of thing) and displays that. The buttons also grey out instead of disappearing.
You can see it at
http://www.stirrdup.com if you're logged in if anyone is interested.
I thought I had seen this sort of thing requested somewhere or another. I'll throw it together and upload it somewhere if anyone wants it, though I don't know how tough it would be to edit it to work with a default installation.
Thanks Abe!