Launch date: August 7, 2001

Fatal flaw(s): Extremely exploitable 

Internet Explorer has never been the shinning beacon of Internet security, but you know things are bad when the U.S. Computer Emergency Readiness Team (CERT) tells users to use any other browser besides IE 6 if they want their computers to remain free of malware. Why? Because it felt that people who used IE 6 had a greater chance of getting infected with the Scob or Download.Ject keylogger which would steal valuable personal info. Of course, Microsoft fixed the whole that allowed this to happen, but it was too late. The flood gates were open and IE's reputation got washed away.