It's basically an MMORPG(Massively multiplayer online role-playing game), where you can create your own surperhero or villian.
DC Universe™ Online is the only next-generation massively multiplayer online action game that delivers unparalleled physics-powered combat set in the DC Universe™. This genre-defining game puts the power of the DC Super Heroes and villains into the palm of your hands…
The next legend is YOU!
---Experience the power of visceral combat where you control every blow your character strikes, delivering a level of action that is unparalleled in the MMO segment.
---Choose your side -- superhero or villain -- as you battle to save or conquer the universe.
---Fight alongside or against your favorite DC heroes and villains including Batman, The Joker, Superman, Wonder Woman and others… The next legend is YOU!
---Experience the intensity of a world created in the artistic vision of legendary comic book artist Jim Lee.
---Take advantage of the state-of-the-art physics engine and use objects in the world around you as weapons, including even your enemies!
---Players will create their own custom DC-style hero or villain, each with a unique look and combination of superpowers.
---Embark on heroic or villainous story-driven adventures penned by famous DC writers including Geoff Johns and Marv Wolfman.
---Gameplay is optimized for both the PS3 computer entertainment system and PC.
---Explore the DC Universe; walk the darkened streets of Gotham City, investigate the mysteries of the futuristic cityscape of Metropolis and travel to legendary locations including Arkham Asylum and the Justice League of America Watchtower.~~~DCUO Official Website
Also that wasn't mention is that you can play the game two ways. In PvE or PvP. For those who don't know what that is PvE means Player v. Environment meaning that a player can explore freely without being attacked by other players, whereas in PvP(Player v. Player) the player can get attacked by other players that are on the opposite side(hero can attack villian and vice-versa). I play the game in PvP and haven't gotten attacked yet, I guess it really depends on what time and what players are playing. Also, the game is pretty neat once you get the hang of it. The only downside I had was the download time it took for me to get the game through the Steam client, but I also think that it could've been faster if it wasn't for my brothers playing online in the Wii or my Dad also on his computer. So it may vary on your computer speed, otherwise the game was very easy to install and took no effort.
Also when you create your character you have the option to make your character small, medium(normal "human" size) or large. For the abilities/powers it can be Custom or Inspired by a Hero/Villain. I didn't choose the "Inspired by" option so I don't know what options they have. Once you pick Custom you can choose to be a Hero or Villain, your personality(powerful, serious, primal, ect.), your Mentor(Superman, Batman, Joker, ect.[dependent on side]), your Power(fire, ice, gadgets, mental, nature, or sorcery), your Movement Mode(flight, acrobatics, or super-speed), and your weapon(bow, brawling, super-pistol, ect.). Once done, you have the option to change your outfit, accessories, skin color or texture(leopard, lion, tiger, ect.), hair color, eye color, and the color of the outfit. Once done, you get to choose your Hero/villain name. I like that you can have a very customizable hero/villain and you can even change the colors of the outfit, also each piece of the outfit is customizable.
Anyway, I think that's enough information for now......