Comic Chat is a piece of Internet history, but I remember that it was somewhat reviled when I first started being active on IRC. This was around 2002, so it was probably due to some cultural memory rather than anyone having actually used it in years.

The issue, as I remember it, is that Comic Chat extended the IRC protocol with support for explicitly indicating the appearance and emoting of your comic character, rather than relying entirely on contextual cues. This was essentially done by adding some nonsense string to every message, which presumably could be decoded by other Comic Chat users, but read like spammy noise to everyone else. I know it did that, because I remember downloading Comic Chat to check it out, but I forget whether it was the default or not.