Viner is a viewer for the Vine video sharing network. The app lets you register, see you personal timeline, search for and follow your friends, like or comment on their vines, change your settings, see the "popular now" or "editor’s pick" timeline and much more, all in a lovely Metro-style user interface.
Of note however is that the app does not let you upload Vines, as that would entail hacking Amazon’s Content Delivery Network. This is however something another Windows Phone Vine app 6sec, is working on, which should be considered before spending $0.99 on this app.
The app is $0.99 with a free trial and can be found in the Windows Phone Store here.