writes "Mastercard has cut out third parties from charging on behalf of merchants. This affects folks paying their auctions and goods via Paypal, Yahoo! Paydirect, and potentially ebay's Billpoint. It may also affect Paypal's Mastercard-backed Debit Card, but there's no word from Paypal as far as I can tell."
Word has it paypal is trying to negotiate a side deal with Mastercard.