sorry for the rant.
Martin Gregorie, meet Adrian Esdaile. He'll take you over into the corner and explain what steampunk is for an hour or so, pausing only occasionally to rant at you ( I mean really, not knowing what steampunk is? I bet you aren't fully versed in the mundane SF manifesto either. How dare you call yourself a SF fan? How dare you have an interest in IT without having a thorough knowledge of SF sub-genres? How dare you even call yourself a human being? (it works best if you imagine the voice rising to a hysterical squeak)).
Next time either of you post, can you use a little common sense first (and in martin's case, wikipedia, or google)? Yes, steampunk exists, and is a well known SF subgenre, within the SF communities. No, SF fans and IT wonks are not a perfect overlap. A one line footnoted description seems a reasonable concession to me.
But then again, I'm not a eletist "all nerds must have knowledge in my areas of interest" wanker. And a one line footnote should be enough to have anyone with little enough knowledge about SF to not recognize the term either checking the usual sources before making an idiot post, or accepting the footnote at face value and not making an idiot post.