The desires of others to interact with you are influenced by your reputation. Being mean makes business suffer.
There is a difference between feedback of transactions, and reputation ratings. Feedback, such as on eBay, serves as a way for the buyer to help or hinder the seller.
A reputation rating can be as complex as a system designed to boil down many different interactions into a concise statement, or it could be as simple as a number 1 through 10.
A rep rating is more abstracted away than one-off feedbacks.
What system, I wonder, will evolve to fill this need of knowing reputations?