It's Internet Relay Chat. It's a completely old school chatroom client where people can get on and roleplay being melting candles or ottomans for their favorite celebrities or something and illegally share files. Now though, technology has progressed beyond the point where we need to rely on IRC for piracy and it's just complicated enough for the average fetishist to not want to bother with it. We are going to use it to call each other mean names 24/7.
Edit: