Vine (a mobile video sharing service owned by Twitter) is going to be shut down in the coming months. A release from the Vine team confirmed the plans to permanently close down the service.
Your Vines will still be intact and Twitter will keep the website alive so that people can still watch the videos but it will no longer be accepting new uploads or users.
http://www.yugatech.com/news/vine-will-be-closed-down/