Twitter has announced that users will have the ability to record, edit and share 30-second videos within the Twitter app on iPhone and Android mobile devices. The videos will post within users' timelines just as other tweets do. The feature has been teased for a while and will roll out over the next few days.
I haven't gained access to the video feature yet, but if it works as easily as Twitter describes it, I think it will be a very valuable addition. Of course Twitter has already offered video via its Vine app, but I see Twitter's native video feature as having 2 distinct advantages: first, eliminating the step of having to switch back and forth between the Vine and Twitter apps and second, Twitter's more flexible 30-second length.