C-Ban meaning Community Ban.
So the idea it to use the normal way of banning someone with a .txt file and storing their name, but the C-Ban.txt can be uploaded to a website and basicaly all the servers tied to a community (eg. using IRC) can set their C-Ban to that location having the list of users banned on each server by having their name in one file,
Maybe the /cban command should also apply the user to the "banned.txt" aswell to be sure just incase of websites being down for maintenence.