@ovidiu: Regarding verification, the plugin has 2 "modes". In the first instance you can allow anyone who likes to place a bid on the auction. You have the option to delete bids you think may be dodgy from the auction backend, in which case the next bid in line reverts to being the winner of the auction. You also have the option of restricting bidding to users who are registered with your blog (i.e. have a WordPress account). You can choose to moderate these users through WordPress user administration and apply any verification process you wish.

Regarding performance the plugin is designed to be as lightweight as possible. The popup uses AJAX calls to refresh its data so that the whole page doesn't have to be refreshed. Besides the actual bid placing, most of the other DB calls are fine grained reads so it should scale quite nicely.

Hope this helps

Hope this helps.