I sell mainly books and have loads of items listed already with additions almost daily. sales have, to be honest, been fairly poor but selling a few titles every month at least makes the relisting button a worthwhile exercise.
I've noticed a lot of new bidders coming to the site (the fact they have 0 or low feedback would indicate this) which is great news, and I hope the trend continues. But I'm also getting an increase in non-paying winning bidders, which as any seller will know, is extremely frustrating. I've just ignored and deleted the sales from my history up until now. But NO MORE, I've started recording sales as non payment and leaving negative feedback. I wouldn't mind quite so much if they contacted me or responded to emails I send to them but nothing. As I promise next day posting and leave the house for work at 8.00, I try to speed things up by wrapping the item as soon as the auction (or even through the Buy It Now option) finishes - I don't address the item, just in case it's another non-payer.
I really feel that auction sites should start naming and shaming non-payers - even if it's with a RED STAR or CROSS next to the bidder's ID - thus telling everyone that this person has history of non payment. We, as sellers, are, quite rightly, expected to fulfil our side of the deal by describing the item correctly, packing it safely and appropriately and posting it when we say we will, surely it's not unreasonably to ask a buyer to fulfil their part of the transaction as well?