In case anybody wants some decent facts on this issue, Wikipedia has a pretty good article.
http://en.wikipedia.org/wiki/Trademark_infringement I'm not a lawyer, but I published a book on IP for developers a number of years ago and learned a lot in the process. In the end, it is extraordinarily unlikely that anybody could possibly fail to infringe when using "Twitter" and/or their logo in a product or service name that is based on Twitter. That inevitably could cause confusion about whether or not it is from the company Twitter or not. Infringement has nothing to do with whether or not the infringement is connected with a "good" or "bad" use, such as spamming, etc. It will be interesting to see what they do with "tweet." Many attorneys advise that if you want to preserve rights in a mark, you have to use it only as a proper adjective. Are they going to grant everybody permission to use "tweet" but only that way? I'll send you a Tweet(tm) message? Seems unlikely. Tweet has become a noun and a verb, which I suspect means it is fated to become genericized, if it hasn't already. Nick
