It's not a silly response. The thing about IRC is that there's channels, and you chat with people in those channels. The deal with Twitter is you both publish and subscribe to short messages, but there's no enforcement of reciprocity -- I don't have to follow someone just because they follow me. There are replies, but that's not the same thing, and Twitter is starting to give people more tools to restrict replies to their Tweets, making the platform even less reciprocal. Everyone in an IRC channel gets the same experience, everyone on Twitter gets a unique experience.