I just read Coelacanth: Lessons from Doom and I just realized that Minecraft is the new Doom. If you don't believe me, find a teenager that has a computer (or smartphone, or tablet) that hasn't played Minecraft.
Doom revolutionized gaming, not by making the FPS technologically possible (thought this is a big deal), but because it spawned a multitude of user generated mods and made it relatively easy and open to do this. This, in turn, incited myriads of hacker youth to build their own mods, edit levels, even (in my case) buy books on graphics programming and learn about BSPs, GPUs, ASM coding, optimizing C code, and other esoteria that I would have ignored.
Frankly, the almost the entire gaming industry owes a debt of gratitude for inspiring the current flock (actually, we're probably on the second or third generation now) of hackers who saw success building their own games with toolkits provided by the makers of Doom. This seems to have been largely ignored up until quite recently by the business side of the gaming industry until quite recently. Some games, such as Mod Nation Racers, the Tony Hawk series, and Little Big Planet, have tapped into the idea of enabling level editing (it's pretty standard fare at this point), but there's still a gap between that and truly modding the game. In these games you generally can't affect fundamental parts of the game and the editors are, in fact, quite oversimplified (not entirely a bad thing BTW).
Minecraft and Doom, on the other hand, are built to enable hackers to expand what is possible within the game via Mods. This enables players who are aspiring developers to actually enhance the capabilities of the game beyond what the original developers had imagined. The idea of making things modifiable isn't new, but actually endorsing a tinker/hacker culture and finding ways to still make money on the product is commendable.