Vine videos aren't awfully long, and that becomes even more apparent when you're scrolling through a profile's post history. So to save some of the hassle of dragging and clicking every six seconds the app will now autoplay an entire channel's videos in succession. It comes by way of hitting the new "watch" button on Android and iOS. Want to go old fashioned and let that clip loop a few times before moving onto the next? It's still totally an option, just tap and hold on the video.
If you're thinking this is a bit like the TV Mode update the web version got a few years back, you aren't wrong. Just to put things into perspective you could've watched around 1,752,000 Vines in that time. You know, in case you were wondering.