Is Twitter heading toward a future in video?

Everybody and their mother has attempted to create “Instagram for video,” and it’s possible Twitter is joining the club.
CEO Dick Costolo sent a tweet Wednesday morning that included a short video that auto-plays when you click to expand his tweet, raising some questions about the company’s intended future in relation to video:

Twitter only rolled out expanded tweets with viewable in-stream media in June 2012, but it’s already become a core part of the Twitter experience as the company moves further toward working with brands on advertising and marketing.
As the company continues to add more and more functionality to expanded tweets, making them more like headlines over stories than 140 character thoughts, it’s worth asking, as Matt Buchanan did for Buzzfeed, what exactly a tweet is these days — it’s come pretty far from its SMS roots. And as David Holmes wrote for Pando Daily, expanded tweets and all of the multimedia content they deliver raise important questions about media ownership across the web.
Costolo’s tweet is especially interesting because the video he shared isn’t just a traditional video embedded through a service like YouTube (and other sites like Ouyala which already allow for video embeds). The video comes from Vine, the video-sharing startup that AllThingsD reported in October had been acquired by Twitter, although the companies never formally announced it. Twitter declined to comment on Costolo’s tweet or the future of Vine, but the Financial Review reported that Vine could be working with Twitter¬†on six second video embeds.
But if Twitter figured out how to incorporate auto-play videos into the newsfeed, it could be a way for the company to make moves in a space that hasn’t yet seen a clear distribution leader, especially after the company lost out on bids for Instagram.

Update: Peter Kafka at AllThingsD is reporting that Vine plans to launch a video service as early as Thursday but that it will remain a stand-alone app for now, and will not be immediately integrated into Twitter.