Any other MMORPGs would be your best bet. For a few examples, Final Fantasy XI, Age of Conan, Everquest, etc.
war hammer online
No
Runescape is somewhat like world of warcraft, though it is not a complex, it is free.
There is World of Warcraft, but I wouldn't intend making that a hobby, it can be an expensive one.
No, there are other games bigger like World of Warcraft.
World of Warcraft cannot be played offline - it's an online game that requires server access to run. With regards to downtime, the realms are offline on Tuesdays (US) or Wednesdays (EU) for scheduled maintenance.
It seems that World of Warcraft has certain similarities.
runescape, lord of the rings online, guild wars
Yes. World of Warcraft is a MMORPG (Massive Multiplayer Online Role Play Game) game. Which makes it only online play.
The simple answer to your question is yes, you can go online, but you cannot play World of Warcraft: The Burning Crusade offline like you could in the classic RTS Warcraft games.
Rappelz, Cabal, FF online the only good nominations
Only World of Warcraft, but that game requires a lot of downloads. and feudalism