Twitter has been trying to diversify its products lately
Twitter is starting to act more like a big tech company, Facebook, Google and so on, that it is and isn't in equal measure. The biggest example is the slow expansion beyond the core product, like the up and coming video-sharing addition based on Vine, the company Twitter bought last year.The first video tweet, based on technology designed by Vine, was posted by Twitter CEO Dick Costolo. Vine is not technically live yet, but it could be coming very soon now.
Similar to Twitter's ethos, though that it's not living up to all that much anymore, Vine videos are only six seconds long, or shorter.
Twitter has the scale to make this work and Vine could, presumably become quite popular. But there have been so many companies trying to create the Instagram of video in the last year alone, none of them successfully, that it's hard to keep track of all of them.
Vine, while under Twitter's umbrella, is still operating quite independently and, at least at first, won't be built into Twitter, it will be a stand-alone app.