You're right, user B could make incorrect (to me) ratings about other users. Similar to what you say about derived and produced information, I would have "pers

You're right, user B could make incorrect (to me) ratings about other users. Similar to what you say about derived and produced information, I would have "personal" and "external" ratings. My personal rating for user C (that I make after reading some of their posts) would override all my other external contacts ratings of user C. Over time, if I have a high percentage of different personal ratings from user B's ratings, then the system would apply less weight to his ratings for other users.