Rating the deal itself is the same as rating the buyer or seller. I mean you rating the buyer or seller based on how the sale went right? Yes.
So, if someone traded you a computer for a television, wouldn't you rate on how the transaction went.
On ebay and any other feedback system, you don't rate the deal. You rate the seller for example on how good he was with customer service, or how fast he shipped etc. So if you buy an item using ebay, and he emailed you that day, and then you recieved the item in a week, you would rate him positive right?
Now if the seller never contacted you and sent the item a month late, you'd probably rate him neutral or negative because he was terrible as a seller.
Now, if you are the seller, and a buyer buys something, then he pays right away, you'd give him good feedback right? Yes.
If you are the seller and the buyer waits 2 weeks to pay, or doesn't pay at all, what do you rate him? Negative obviously.
Now, in a trade. Say you both agree to a trade. You are sending him your tv, he is sending you a computer. Well what happens if you send the tv and you never get the computer? Are you not going to leave him feedback on how the trade went? No. You are going to want others to know that you had a trade arranged and you never got the product that you wanted.
Another example is if you two are arranging a trade and he's trying to lowball you left and right, and finally you agree on something but it took forever and he acted crappy about it. You might not want to leave negative feedback because you both finally agreed on a trade, but you also didn't like he he did things so you will leave him neutral feedback.
Now as for positive feedback, say you find someone wanting to trade your tv for a computer. You both recieve your items promptly, so you would rate the feedback as positive because it was exactly as described and there were no problems.
Here's a feedback overview from eBay -
http://pages.ebay.com/help/feedback/...-overview.html
"eBay members who have completed a transaction with you can leave feedback about their experience."
You made the point "For my opinion, always the seller and the buyer should rate and should be rated - like in ebay. I still don't understand the sense of rating the deal itself - regardless if it was a sale or a trade."
That is exactly what takes place in this hack. You rate a buyer or seller of an item that you recieved or sent. I don't understand exactly what you aren't understanding.
You believe that both the seller and buyer should be rated and that's what's happening in a item being sold, or items being traded. Either way it involves 2 parties.
So my main question is why is it NOT sensible to rate a trade?
Maybe if you answered that I could help you answer your questions.