Skype выпустил достаточно официальное и подробное объяснение проблемы своей нестабильности на прошлой неделе:
On Thursday, 16th August 2007, the Skype peer-to-peer network became unstable and suffered a critical disruption. The disruption was initiated by a massive restart of our user’s computers across the globe within a very short timeframe as they re-booted after receiving a routine software update.
The abnormally high number of restarts affected Skype’s network resources. This caused a flood of log-in requests, which, combined with the lack of peer-to-peer network resources, prompted a chain reaction that had a critical impact.
Normally Skype’s peer-to-peer network has an inbuilt ability to self-heal, however, this event revealed a previously unseen software bug within the network resource allocation algorithm which prevented the self-healing function from working quickly. Regrettably, as a result of this disruption, Skype was unavailable to the majority of its users for approximately two days.
The issue has now been identified explicitly within Skype. We can confirm categorically that no malicious activities were attributed or that our users’ security was not, at any point, at risk.
Полагаю, что тема хакерских атак может быть, наконец, закрыта. Насчет всего остального — всё когда-то бывает в первый раз :).