Coming back to that "usually", now if you were to pay for feedback about your site, you can argue that what you are paying for is more akin to a service rather than a giveaway / game / raffle / etc. In that case, a thread in Services that collects said feedback and pays out for said feedback in BTC is probably on topic (as long as it isn't trying to circumvent the rules with the feedback being just the word "good" or "bad"). However, asking for that feedback to be posted on an ANN thread seems more like a ploy to pump up the ANN thread with activity / posts rather than a legitimate attempt at getting constructive feedback.
If you put it like this, I can agree to it 
And I vaguely remember reading something similar a while back: paying for reviews should happen on the Services board.No offense but if you want the 100% accurate rules, ask Bitcointalk's owner.
That's not going to happen:I don't believe in having a set of hard rules which is to be applied to all cases.