IDC analyst Rebecca Swensen said the Skype outage -- traced to Microsoft's set of Windows updates rolled out last week -- serves as a reminder that the reliability of VoIP is not the same as traditional telephone networks, but she pointed out that, historically, Skype's network has been reliable, and said that the reliability of VoIP is improving.

Skype said that the disruption of its service that occurred globally last week had been triggered by a massive rebooting of Windows computers around the world, and that no malicious activities or security  issues had been involved.

The high number of restarts, which occurred as the Windows computers rebooted after receiving a routine set of patches through Windows Update, "affected Skype's network resources," wrote Skype spokesperson Villu Arak on Monday morning. The reboot unleashed a flood of log-in requests, which -- when combined with the lack of existing peer-to-peer network resources because of the rebooting -- "prompted a chain reaction that had a critical impact."

Normally Skype's peer-to-peer network has an inbuilt ability to self-heal, Arak observed. However, last week's interruption of service "revealed a previously unseen software bug within the network resource allocation algorithm which prevented the self-healing function from working quickly," he explained.