According to a study by video tech firm Unruly, 6-second Vine videos are being posted to Twitter at the rate of 9 per second, which is up from 5 per second two months ago. The news comes amid talk of a brewing war between Twitter, which owns Vine, and Facebook’s Instagram, which just launched a short video service of its own. Since launching in January, Vine videos have found a niche with consumers who enjoy sharing videos with their friends, but they’ve also found a place at arts forums like the Tribeca Film Festival (see the Bambi clip below), and have attracted copyright controversy. The Unruly survey says that Vine now has more than 13 million users, and that the service is popular with advertisers since branded Vines are four times more likely to be shared than video ads. Despite the hype, not everyone is enamored with the idea of sharing short video on social media.