First off, I think FarmSteader's idea about Kudos is very good, although I fear it might refrain people from donating real credits, defeating the purpose of the site. The concept works though. The same principle is used on another forum I visit regularly,
www.tek-tips.com. Any user can flag a post as very helpful, and the author will receive a star for it. I have gathered around 25 stars and it feels good and it motivates you to help other people better.
My own ideas about improving www.donationcoder.com:1. I've posted this before in another topic: I'd like to see a section where coders in particular can post FAQs, tutorials or 'Tips-n-Tricks' dealing with subjects or language elements they are proficient in. These posts can be about programming in general or a specific language topic.
2. I'd like to see an option where I can be notified of an important post by the staff. This could be any new topic in the 'Official Announcements' board. If you put this option in the profile settings and enable it by default, then all users will be notified of new topics like this one. This will, in my opinion, greatly improve the feedback on the site with regard to user opinions. For whatever reason, some users cannot or will not browse through each forum board regularly and therefore miss important threads.