Meta Block Ids.
if al wanted to he could code 10k+ different kinds of generators and it would only use 1 Block Id in the process. Not that he will bother with something so useless like that.
That's what Eloraam does or my CropBlock is capable of. IC Machine run on sole metadata though, it's simpler and less CPU-effective. And less bugged.
@LightnignRod: The second "Weather" was announced to come in minecraft (was that back in Beta 1.5? Ol' times), my IC thread was getting spammed with Lightning Rod suggestions.
Given Lightning Rods would be near useless in first place and aren't exactly ned either, idea is denied and generally frowned upon, because it's a prime example of people ignoring the Search function and cluttering the forum with useless threads on a weekly basis.