I have seen a few vBulletin forums implement something called a "thank you button". It's a button that any forum member can click to show their gratitude for someone's post:

http://www.vbulletin.org/forum/showthread.php?t=231666

It isn't an official add-on, but it is extremely well supported and very popular.

I really think this feature would help add to the community support aspect of QRZ.com. We have a thriving technical help section, and this would be one great way for people to give quantifiable kudos to people who help them.