Twitter has filed a trademark for the term "subtweet."
Subtweets — that thing where you talk about someone in the open forum that is Twitter but don't specifically mention them so they totally know what you mean and, like, everyone who's in on the situation knows what you mean, but sometimes some people have to ask, "Who is he talking about and why is he so angry at them, is this a work thing or a relationship thing or something else entirely it's pretty vague??" — are getting trademarked by Twitter.
Subtweet™.
This isn't the first time Twitter's trademarked a term coined for behavior on the social network. "Tweetstorms," in which someone keeps talking to themself to get around the 140-character limit of tweets and make a Big, Important point, were trademarked back in April.
Twitter's almost certainly grabbing these up for a brand protection; both have the word "tweet" in them, which is what you do on Twitter, so Twitter wants to own the words.
If you're going to tweet about the news, we suggest something like "I guess some companies think they have to trademark everything," or "So weird that some people will go to any lengths to control things," or "I honestly don't understand what we're even doing here."