Skype may provide untraceable hacker hideouts. It has been discovered that:
VOIP (Voice Over Internet Protocol) applications could provide excellent cover for launching denial of service attacks.
In such attacks computers are being hijacked by hackers and turned into so-called "zombies" in order to bombard a Web site or e-mail server with page requests or e-mails. The aim of the attack is that the site or entire network collapses under the pressure.
VOIP cuts a voice conversation into digital bits and hackers can use those data streams for cover, making it almost impossible to trace the source of an attack.