I've seen this in use on other sites, and I'm adding it here based on how I've seen it work, and user feedback from certain members.
This feature will allow feedback to be listed from for sale / trade forum deals and will allow for instant tracking on user profiles.
In order to prevent abuse, only threads from the exchange forums will be eligible for feedback. When leaving feedback, you will need to provide a URL from a specific thread in the Exchange. If you try to leave feedback on something not in the Exchange forums, it won't let you.
The system isn't foolproof, but I'm going to be very harsh on abuse.
Current settings:
Users have 5 minutes to edit / delete feedback they leave.
You must wait 24 hours before you can rate the same person again, so no multiple ratings / dings on the same person in the same day.
There is a 30 day max time limit on leaving return feedback once you've received feedback from someone.
There is a 5 person, per day limit for leaving feedback for "new traders" - if you have less than 5 feedback, you are considered a "new trader"