Twitter’s Application for “Tweet” Rejected
Twitter can’t seem to catch a break when it comes to trademarks. The United States Patent and Trademark Office has preliminarily denied Twitter’s bid to trademark the word “tweet.” Twitter appears to have lost the race, not against time to prevent their potential trademark from becoming generic, but against three other companies that filed applications containing the word “tweet.”
TweetMarks, Cotweet, and TweetPhoto all submitted trademark applications for their respective names that predate Twitter’s filing. What’s ironic is that these are all independent sites that were created to piggyback onto Twitter! The USPTO wrote that a trademark on “tweet” would likely cause confusion among consumers as to its source. The goal of a trademark is for the public to be able to unequivocally identify a brand.
Twitter has indicated that it even if the trademark is ultimately registered, it would allow liberal use of “tweet” unless it would be injurious to the company. Now it seems that Twitter will be unable to protect the term at all. No matter what the outcome, millions will still be tweeting, including me!
I can think of other grounds upon which "tweet" would be denied registration. Trademarks should describe a product or service. They cannot be generic nouns, like "milk," "car," or "scissor." I have heard the word used as a noun ("Post a tweet so I'll know what you are doing"). Similarly, trademarks cannot be used as verbs ("Her thumbs are sore from tweeting on her phone"). Thus, trademark registration should only be granted if "tweet" was used as an adjective, as in, "Your tweet micro-blog is always updated," or "Stop sending tweet messages at the dinner table."
I can help you navigate the subtle trademark registration rules. Let me know if you have a question about them.

