I was thinking about this just the other day. I decided the best thing to do would be to say nothing at all, then Randall Munroe of xkcd went and ruined it. Link
I've never felt the urge to claim Firsties, largely because whenever I arrive at a board that hasn't been posted to yet, by the time I compose and submit my post, there's usually one or more comments already (I'm a very slow typist), so I'd look pretty stupid to have claimed "First!"
Hah, "first post" dying? No way, most popular video's on YT still suffer from this syndrome, I've never really been annoyed by it, it's a part of our internet traditions, calling the first post, and then calling the first poster an idiot followed up by several clever responses on what the first poster was in fact first at.
It's an evolving tradition.
Wait did I just make a post about posts under a cartoon about posts? Postception!