Advertisements on Lesswrong (like lsusr's now-deleted "Want To Hire Me?" post) are good, because they let the users of this site conduct mutually-beneficial trade.
I disagree with Ben Pace in the sibling comment; advertisements should be top-level posts, because any other kind of post won't get many eyeballs on it. If users don't find the advertised proposition useful, if the post is deceptive or annoying, then they should simply downvote the ad.
you can get these principles in other ways
I got them via cultural immersion. I just lurked here for several months while my brain adapted to how the people here think. Lurk moar!
Even if only a single person's values are extrapolated, I think things would still be basically fine. While power corrupts, it takes time do so. Value lock-in at the moment of creation of the AI prevents it from tracking (what would be the) power-warped values of its creator.
Or a decision market!