We have been recently working on a “points” version of HelpShare. Amazon has gone so far as to introduce 2 points schemes within their Askville site. One for answer value (“experience points”), and one for participation (“Quest Coins”).
The quest coins reward community members for participating in questions they didn’t ask. Presumably this works as a spam filter for the site and makes the community more active. I’m not sure the second currency is worthwhile because it adds complexity to the user experience. However, different classes of users (askers, answerers, and questers) will each care about different currencies in different ways. Overall,I think it will be effective means to motivate community moderators.
Askville also has a separate virtual currency called Quest coins which users will earn for various actions, including asking a question, voting on answers, providing answers, etc… We’ve kept experience points separate from Quest coins in order to keep experience points tied directly to how well you answer questions in various topics, while Quest coins will be a currency that will be earned (or lost) through various different actions each user makes throughout Askville.