Skype denies that the outage is the result of an attack, but still failed both to demonstrate the lack of foundation for the attack announcement and clearly explain the reason that caused this sign-in problem. Standard Public Relation technique.
Recent Skype outage, apparently fault of a denial-of-service attack on the Skype centralized login infrastructure, raises again the intrinsic flaw of designing a service or an application (even partially) based on a centralized network topology.
As the recent facts show, offering a service with a Single Point of Failure creates a “domino effect” whose legal implications (in terms of damages suffered by paying clients) might bear unforeseen consequence. The “flawed-by-design” kind of liability might, indeed, lead to a class action against Skype for having knowingly chosen to build their service on a technical structural weakeness.
Of course, I imagine that should that issue be taken into Court, ICT expert witnesses will play the major role in addressing the underlying technical issues.