Jason Moffatt - why did you buy TwitterJason.com?

Evan gave one answer in that:

What many people don't seem to realize is that registration is not required for
a trademark to exist. If your state requires you to get a dog license and your
dog doesn't have one, it's still a dog, right?

Generally speaking, a trademark exists when one actively uses a word, symbol,
phrase, or any combo of them (at least) "in commerce", otherwise known as a
"common law trademark". You have one if you sell fire extinguishers that bear
the label "Apple" in them and if your market learned to distinctively identify
you as its source. (keyword being distinctively...)

But common law trademarks are generally limited only to their jurisdiction, and
can't be enforced outside that. If you sold Apple fire extinguishers in Indiana,
you cannot enforce your Apple mark in California.

That's where registration comes in. In a manner of speaking, a registration will
enable you to tell others, "hey, folks, we have a trademark for the word Apple
to sell fire extinguishers, and we'll go after you if you sell extinguishers using
our mark even if you didn't know."

Having a registration at the United States Patents and Trademarks Office, or
USPTO, will give you a U.S.-wide trademark. That'll enable you to go after one
who's using your Apple mark to sell extinguishers no matter what state they're
in.

However, one must go through a process at USPTO before they're (hopefully)
granted one, part of which is allowing others to object to your application for
the mark. The reason for that is others might be using the same word for their
own commercial venture and might cause "likelihood of confusion", which TMs
aim to prevent from happening.

So if you filed an application at USPTO for Apple to sell fire extinguishers, plus
you passed their other requirements, USPTO will give others a chance to post
their objection. Big guys like Apple Computers to oppose it, saying your mark
can confuse others with their own.

That's what the Twitter folks are going through right now, based on what Evan
has blogged and Big Mike posted here. Twitter arguably has a trademark (and
their application states what for if you search for it in uspto.gov, although the
link expires if you post it here), but time will tell if USPTO will finally grant them
a Federal registration or not.

One of the risks trademark holders face is called "dilution":

Trademark dilution - Wikipedia, the free encyclopedia

Twitter, like any other mark holder, faces that risk, more so now that Jason et
al have registered domain names bearing it. But like I said, it's up to Twitter if
they decide to go after them or not, or let them continue on if they think it'll
be a win-win situation.

I'm not a lawyer, and I can be wrong on some details. Feel free to check with
licensed and experienced people who do these things for a living.

That's another thought, although that's probably negligible. Still...