Skype Ltd. provided background into the reasons for last week's outage, blaming a massive restart of user computers within a very short timeframe for the disruption.

    Beginning on Thursday, the company's voice-over-IP (VOIP) service experienced a massive outage that lasted for about two days. Skype first identified the problem as a "software issue." (See Software Bug Stings Skype.)

    But details provided on the Skype Website this morning link the outage to Microsoft Corp. (Nasdaq: MSFT - message board) Windows updates. According to Skype spokesman Villu Arak, the service was dragged down by a "flood of login attempts" after users downloaded a routine set of patches through Windows Update and rebooted their computers.

    Combined with a lack of peer-to-peer (P2P) network resources and a "previously unseen bug within the network resource allocation algorithm which prevented the self-healing function from working quickly," the large number of login attempts crippled the Skype network, making the service unavailable to a number of its users.

    In his blog entry this morning, Arak pointed out that last week's disruption was "unprecedented in terms of its impact and scope," and noted that "very few technologies or communications networks are guaranteed to operate without interruptions."

    Jupiter Research analyst DougWilliams believes most Skype users won't be put off by the outage. "From a consumer perspective, you get what you pay for, which is something users need to recognize. For convenience sake, they want these services to work, but if it's down for a day or two, they'd rely on other services."

    However, Williams thinks the outage could become a problem as parent company eBay Inc. (Nasdaq: EBAY - message board) tries to monetize Skype's traffic by providing premium services such as outbound calling to wireline or wireless phones, inbound calling, and voicemail.