Niklas Zennström has stepped down as chief executive of Skype.

Zennström is chief strategy officer at eBay, which owns Skype, and will temporarily take over the position of executive chairman at Skype while a permanent replacement is sought.

He has been appointed as non-executive chairman of Skype's board of directors.

The management change comes shortly after Skype was hit by an embarrassing and widely publicised two-day outage in August.

The service interruption was traced back to an error in the Skype software that was triggered by a Microsoft update. A forced reboot after the Windows update effectively launched a denial-of-service attack against the VoIP service.

EBay acquired Skype for $2.6bn in 2005, but critics have always questioned the auction service's ability to earn back the acquisition sum.

EBay had argued that it would increase Skype's appeal by offering premium services such as the ability to call the seller of an auction item.

Skype posted revenues of $90m in its most recent quarter, and boasts 220 million registered users.

However, eBay chief executive Meg Whitman admitted in a conference call discussing the June 2007 earnings that Skype had failed to deliver the desired level of user activity.

Since the sale of Skype to eBay, Zennström has started up a new online video company under the Joost brand. The service was officially unveiled last January.

A spokesperson for eBay did not immediately return a call requesting comment on the reason for Zennström's departure.