I am the type who is always logged on IRC, but never have anything to talk about. Sure I will talk at times, but I can never start a conversation that lasts more than two to three lines. I can only assume that the large majority of people who CAN talk on IRC have that very same problem.
Either that, or you know, bad timing. The impression I get is that a lot of IRC logs can simply boil down to:
Some User: Hey, "Specified User". Are you there?
*Specified user is logged on, but is afk and never responds*
SOME TIME LATER
Specified User: Hey, was here someone asking for me?
*Person asking is no longer there*
And to answer Oblivion's very important question: it is simply far too difficult to choose just one. Until they break down and finally make an anime adaptation of Firefly, I will never have a truly concrete answer to that question.