I feel that the seller should leave feedback upon receipt of payment. After all, at this point the buyer has completed his portion of the transaction.

Lately, most of the sellers I have bought from are not posting feedback. I'm even getting e-mails saying something like "You must have received your item by now, please leave feedback and I will do the same". I usually respond with a note saying that I feel it is the seller's responsibility to leave feedback first and that I would leave feedback only after I receive feedback from the seller. Some comply, some ignore me and drop the subject.

Recently I had a seller tell me that it was my obligation to leave feedback first so that he would know I was satisfied with the item and I should do so because these were the terms of his sale. I told him that he had a lot of nerve contacting me and demanding feedback from me (the buyer) first. I never heard from him again.