It has been reported that skype reads files like /etc/passwd under linux - something it has no business to do. That brings us to the fundamental question, how much spyware is skype loaded with. As to how this was found out, the fact that skype reads /etc/passwd, follow the link below to find out
http://forum.skype.com/index.php?showtopic=95261
How much spyware does skype have?