Frankly it wouldn't mean anything, but Noob's and member who know no better, have a default list, which means, when users who have been wrongly nailed by someone on the default trust list. Every new user see's a BIG RED Extreme Caution warning.
Effecting, sometimes, if people even reply to you.
So although I no longer have any faith in the system. Many users still do.
If the system was used as stated, it would be fine really.
Risked BTC amount is money that the person could have stolen or did steal. For example, if you do a currency trade where the other person sends first, your feedback for them would have 0 risked BTC and their feedback for you would have risked BTC equal to the BTC value of the trade.
Type:
Positive - You trust this person or had a successful trade.
Neutral - Comments. Your rating will not affect this person's trust score.
Negative - You were scammed or you strongly believe that this person is a scammer.