Yes. You have to have the first WoW and all the expansions leading up to Cataclysm.
You don't need to buy The Burning Crusade anymore because it comes with the first WoW, but you do have to buy:
Wrath of the Lich King
and then you can buy World of Warcraft: Cataclysm
There is no world of warcraft 3. There is world of warcraft, and warcraft 3. Unless you want to refer to Cataclysm. If so then no, you'd fail.
Yes, you can start from level 1 and go right through to level 85 however, you will need to download the other 3 games first World of Warcraft then World of Warcraft: The Burning Crusade, then World of Warcraft: Wrath of the Lich King and finally Cataclysm.
No, you just download and play world of warcraft, you need Cataclysm when you reach level 80 in the game.
Normally you don't need to buy any games to play it's sequal.
There is only one World of Warcraft. It has several expansions though. They are (in order of when they were released): Burning Crusade (which is included with the original WoW), Wrath of the Lich King, Cataclysm, and Mists of Pandaria (not released yet).
Yes, you need not only the regular World of Warcraft game, you need the two other expansions in order to play Cataclysm. This is because if you level to level 60 then you will need to level to level 70 (Burning Crusade Expansion) if you want to continue leveling. Then you will need to level to level 80 (Wrath of the Lich King) and then finally level 85 (Cataclysm). You do not have to level to 85 but most people who buy the expansion do. You will need: World of Warcraft (original/regular game) The Burning Crusade (now included for free in the basic version of the game) Wrath of the Lich King
Priivate servers are ilegal, i would suggest keeping away from them.
Yes. But, if you want to play cataclysm for example, you would have to buy ALL the other expansions.
There is only one World of Warcraft game. It has a few expansions though. You should start out with the vanilla (the original game) wow, and decide if you like it. Then you can add each expansion in order, Burning Crusade, Wrath of the Lich King, and finally Cataclysm. You need to add each in order though, as each gives you access to new levels and content. If you want to play cataclysm content, then you need to first upgrade your account to Burning Crusade and then upgrade to Wrath of the Lich King, and finally Cataclysm.
Cataclysm will be closed beta, meaning you can not play it without a key that Blizzard gives you. The beta will act like the PTR, but will be seperate. For more information look at the site in the related links
If with Cat you mean a Cat Druid, then yes you would have to play World of Warcraft. If you simply want to play a game with cats, there are plenty of pet-raising games around, and the online MMO Tera which is scheduled to be released in 2011 will feature the Popori race, which are cute anthropomorphic animals. I think what the asker meant was do you need World of Warcraft in order to play Cataclysm. If that was the question, then yes you do need the original World of Warcraft and also the Burning Crusade and Wrath of the Lich King expansion.
I liked the Burning Crusade and I'm very anxious to play the new Cataclysm release.