The 3wplayer employs a form of social engineering to infect computers. Seemingly desirable video files, such as recent movies, are released via BitTorrent or other distribution channels. These files resemble conventional AVI files, but are engineered to display a message when played on most media player programs, instructing the user to visit the 3wplayer website and download the software to view the video. The program is bundled with malware that has various undesirable effects, including attempting to disable anti-virus software.
Wildman Productions has created a tool to convert video files compressed for the 3wplayer back to regular AVI files. More details can be found on their site. http://wildman-productions.org/