There's been a lot of talk over Twitter's attempts to trademark the word "tweet" (Twitter has been a trademark of theirs for some time now), but blogger Sam Johnston did some digging and found out that it's unlikely that Twitter will ever be able to trademark this particular word.
Just like the verb "google", tweet and tweeting have become a part of our everyday language. Furthermore, several other companies filed for a similar trademark - "tweetmarks", "cotweet", "tweetphoto." Check Sam's blog for the legal details, but it all boils down to the fact that Twitter will probably never reign over the word "tweet", and - hopefully - no one else will, either.