Trademark...

Let's take Facebook as an example. Let's say "The Facebook" was originally trademarked... would they have need to get a new mark for "Facebook" or would they be considered essentially the same under the rules for Trademarks?

I ask because I am in a similar situation (using "The" in front until it's worthwhile paying for the main URL, which is not in use but the buyer wants an amount I cannot afford to pay for right now).

Help appreciated... thanks!