As a seller I state clearly in all my listings that "I only leave positive feedback once feedback received. This lets me know the buyer has received the item and is happy with it". A buyer of one of my items recently contacted me to say this was the wrong etiquette and made no sense at all. They were not prepared to leave feedback as a buyer until I had left feedback as a seller. The only reason I started doing this was that years ago I sold quite a few items and despite leaving feedback I received no feedback myself. The feedback is, to me, an important part of my selling on ebay. I've sold over 500 items on this basis and last week was the first time any buyer had refused to leave feedback first. I think I will carry on the same, it is up to the prospective buyer to read the listing and then choose if they wish to bid or not.