This is a concept foreign to many CN players.
Let me summarize it for you.
Roleplaying is where you pretend to be someone else while playing a game.
For example, members of the New Sith Order pretend to be Sith, or followers of the Sith (I hate the prequel films and don't really understand the whole Sith idea because I haven't watched most of them) from the Star Wars universe while playing CN.
They are not actually Sith. This is roleplaying.
Recently, there was an incident where the alliance sent a number of messages in the game to another alliance. Some people said the messages were disrespectful.
One person, evidently confused about the meaning of the word roleplaying, said that the messages weren't disrespectful because the Sith were roleplaying their evil personas.
I replied to him, but snipped that little nugget out, which was inappropriate on several levels, not least because it was a discussion of roleplaying in an IC area, i.e. where roleplaying is actually done.
The biggest way in which it was inappropriate though was gross stupidity. If I choose to roleplay a disrespectful person, and then in an IC forum, someone accuses my character of being disrespectful, it is the height of foolishness to say "No, I was just ROLEPLAYING!" Given that's what everyone is doing there to one extent or another.