Tom Keating, chief technology officer for Internet Telephony Magazine, said he's heard from a number of businesses that rely on Skype to keep workers in touch with each other as well as clients. He said the instant-messaging feature is particularly popular with users because it works around many company firewalls.

 

Keating said the outage may be related to some maintenance work Skype completed Wednesday night. He said it's unlikely the problem was caused by an outside attack from hackers.

 

"It's very possible that the change they did with maintenance could have had some unanticipated cascade affect," said Keating.

 

Technology blogger Om Malik said the failure may reveal some weaknesses in the peer-to-peer technology on which Skype relies. Normally, peer-to-peer systems work to route traffic around problems, ensuring a consistent connection.

 

"Venture capitalists who have been funding (peer-to-peer) services should take this as an early warning on the fragility of the whole (peer-to-peer) ecosystem, where a small glitch can cause widespread problems," Malik wrote Thursday on his blog GigaOm.