The term ‘subtweet’ refers to tweeting about someone without using their twitter handle, i.e. tweeting behind people’s backs. The term has been in use for several years.
If successful it would mean that any commercial use of ‘subtweet’ would be prohibited without first gaining permission from Twitter. Also included in the application is ‘sub tweet’ with a space in the middle.
Previously Twitter has attempted to trademark the term ‘tweet’. This application failed due to the widespread public use of the word, superseding Twitter before it could make a claim. In light of this given that the term ‘sub tweet’ has also originated from the public and not from Twitter directly, this application may also suffer a similar fate.
It remains to be seen as to whether Twitter will succeed in their application, if no opposition is filed, Twitter will likely be granted the trademark in a matter of weeks.