According to an article at the Detroit News, Microsoftis Web site was knocked offline for two hours Friday due to a denial-of-service (DoS) attack. Microsoft says that it is working with law enforcement to find the attacker, adding that the attack was unrelated to any flaws in Microsoft software. From the Detroit News:
Microsoft began investigating the outage at the Microsoft.com Web site at about 1:21 p.m. Seattle time, Microsoft said. The site was undergoing a so-called denial-of-service attack, said company spokesman Sean Sundwall.
A denial-of-service attack occurs when a hacker tries to prevent users from viewing a Web site, generally with a flood of traffic.
You can read the full article at the Detroit Newsi Web site.