1) For selfish UCC, take note of Delicious' example and try to drive general relevance without interrupting the selfishness of your users. Delicious prompts me with terms others have used, making my selfish life easier while making relevance of my actions more general.

2) For social UCC, create programmatic mechanisms (like polls or votes or star ratings) that allow people to quantify their point of view on some abstract scale. This will benefit the user (by allowing them to say simply, "I am *very* Republican," for instance) and benefit everyone else -- who can then say, "He's *very* Republican, and I can easily assess where he's coming from."

3) For Selfless UCC, use human editors to manage quality, and try as much as possible to create "superuser" editors to do this for you. The cost-benefit ratio is outstanding, so get over the stone-ageness of it and go make money.