Vine for iOS

When Facebook launched Video on Instagram, some were quick to dig an early grave for Vine -- Twitter's video-only app was surely doomed, right? Wrong. Twitter just revealed that Vine now has over 40 million registered users, or more than triple the 13 million users it claimed before its Android app launch in early June. Twitter hasn't said how many of the new members run Android, but it's clear that Google's platform contributed significantly to the increase. Whether or not Vine maintains its pace is another matter. While Instagram frequently reports active users, the Vine team isn't as specific; there's a chance that some of those 40 million account holders tried Vine and promptly abandoned it. Still, the much larger audience suggests that there's room for more than one short-form mobile video service.