It's really amazing if you stop and think about it. How many years have MMOs, as we know it, been around? I have to admit I wasn't paying attention when they quickly became a part of the mainstream, but it's kind of shocking how long it took for folks to create something that is arguably one of the most tailor-fit scenarios for MMOs since ham and cheese met bread. It's good, too, because I'm kind of sick of being the last hope for the (read: countless) fantasy worlds. No magic, no fairies, no elves; just one Marine, 75mm of bore on a high-velocity cannon, 30 tons of steel and a full salvo of armor-piercing rounds.
World of Tanks is the first working tank battle MMO I've had the pleasure to play. There's others, but I couldn't even get them to start up without crashing so I gave up on them long ago. One thing you can tell about World of Tanks is the team behind it doesn't just like WWII tanks. They love WWII tanks. I do too -- and I was fortunate to be able to jump right into the closed beta. As for the development team's love for vintage tanks, one could immediately tell this by simply the first time I logged in, this particular beauty was available:
The Somua 35f. The Dan Hibiki of the tank world.
While it's stated that only German and Russian armor is available in the closed beta, this is actually a French tank. Quick history lesson: when Germany overran France in 1940, they simply added France's armor to their own numbers. It's as useless in-game as it was when the Russian front kicked in, but it's one of my favorite tanks regardless and I'm impressed that the team is so dedicated as to make sure of its inclusion. On a fun note, while I've currently had many of them destroyed on me, I did manage one certified kill with it. Oorah!
As far as I know, WoT will use the free-to-play, premium cash shop based model that we all know and love (hah!) so well. It seems like they took the best of what actually works from subscription based MMOs like Eve and melded them with the best of Free-To-Play (F2P). The standard F2P gripes don't apply here -- this isn't a function button-bashing marathon like every other MMO; you have to float like a butterfly and sting like a bee. Just because you're rolling out in that shiny premium Sherman Firefly doesn't mean you're not going to get your rear end handed to you by a plucky Panzer II pilot who caught you with your pants down.
Another factor that will appeal to players of certain MMOs -- especially the Eve crowd -- is the chassis-module based aspect of the vehicle. Every item requires training, and you trade in training from battle experience. It's not the slow wait-grind either. Within hours -- in the beta, at least -- you can move up to bigger and badder tanks/modules. This will most certainly be fixed for the final roll-out, mind you.
As I stated above, just about every tank from World War II fits somewhere into the standard MMO class, from the rogue-analogous light tank all the way to the "noob-fit" Soviet battleship-wannabe tanks. It's not going to be hard for a typical career archer to fit themselves into an artillery tank.
Light Tanks: These tiny but quick vehicles are arguably and tactically the most important armor on a team. See, they can point out where the big lumbering Tigers are so artillery can take them out from a distance. You'll die alot but nobody will hate you for it.
Medium Tanks: As far as firepower and mobility go, these are your guys. In fact, they're the most varied single group in the entire game. You'll have highly mobile peashooters like our Somua above, up to a death-dealing T-34/85 that would make a King Tiger crap its pants.
Heavy Tanks: Slow. Powerful. Like light tanks, they are either to your advantage or detriment. There's no middle ground with them -- if a pack of mid-sized gangs up on one, it's over.
Tank Destroyers: These range from fast, lightly-armored variants to nigh-impenetrable unholy terrors that even the largest tank in the game -- the Maus -- would fear. They're almost entirely intended for camoflage and defense, hence the lack of a rotating cupola and their low silhouette. If the enemy gets a bead on you from behind, you're toast.
Self-Propelled Gun: The final word in firepower. These are the big guns that your little guys go hunting targets for. They're essentially glass cannons but with devastating firepower.
(still working on this)
The Maus: Much like Eve, the endgame here is this thing. If you're unaware of what the "Maus" is, just Google it - the second entry on it, to be specific. Be prepared to catch your jaw on its way down.