While eBay might gain some opportunities to do more for its customers by making it easy for them to talk to each other or be involved in the closing stages of auctions, he said, the attractions for Skype users were less clear.

At the moment, most people use Skype to make cheap and easy phone calls via their computer and a broadband link.

"Changing this success formula could have disastrous consequences for customer numbers, particularly given emerging alternatives such as MSN Messenger and Google Talk," Mr Heath told the BBC News website.

John Delaney, principal consultant at analysts Ovum, added: "eBay has definitely overpaid for Skype."