You have made 3.527 posts, on escapist, a place where WoW is talked about every single day.... Sorry i don't belive you have never heard or known WoW prior to the moment you wrote and began this thread...
If for some reason it is true... Welcome to the internets...
And if for some reason you are serious: WoW is a good MMORPG, that continues the story of the old Warcraft RTS games. In it you will have great adventures with hundreds of players, and with a huge world to explore and evolve.
In it you can choose either Allience, that consists in a bunch of ingrats that even though they call themselfs pure and righteous, they have unleashed some of the most terrible monsters upon the world... In it you have the meatbags, the purple meatbags (elves), the blue caddle (draenei), the steroid abusing midgets (dwarfs), the garden gnomes and the awesome werewolfs (worgen).
Then you have the Horde, a union of races that is trying to make a living on a new world. With them you have the talentless goblins (everything they make, breaks), the "drug" abusing Blood Elves, the original Caddle (Tauren), the "second chance" folks (forsaken), the misfortunate Orcs (The Orc story is very sad, filled with bad luck and misfortunes), and the epic, chilling, unwielding, charismatic, and saber tooth Trolls...
Pro-tip: Both allience and Horde are great, and have many interesting places to visit and know about, i myself prefer Horde way better. Try and pick professions like Mining or Herbalism. The Druid class is awesome (transformations and such), and the shaman class if well played, can be a great, powerfull start. Try to visit has many places has you can (cuz it gives good experience and you get to see great things), and save money up to get a mount by lvl 40 or so.... this is if you want to get the game later on...
Have fun...