A message board
and image board
on the Internet
congregate to post various kinds of pictures, flash animations, and discuss things such as anime
. It is the English version of the original Japanese board with a similar system: 2chan.
The system that 4chan uses is Anonymous, so one can safely post one's opinion without worrying. One can use a name and a tripcode (a # followed by a 'password') to gain 'status' on 4chan.