Vine is now available for Kindle Fire. Can Windows Phone and Blackberry versions be far behind?
Instagrammers outnumber Vine users 10-to-1 but how much will that number change as Vine spreads its tendrils to other mobile devices? 

Just launched for Amazon's Kindle Fire, and available now for free from the Amazon App Store,  Twitter's short form video app Vine is seeing a lot of action lately.

First, Vine teased some new features the day before Instagram launched its 15-second video functionality. Although those teaser Vines still remain a mystery, Vine for Android was then updated not once, but twice. (You can read our coverage of the updates here and here.) Other than the spam attack on Instagram over the past few days, there hasn't been any indication that Instagram will continue playing leapfrog with Vine and launch its own app for Kindle Fire.  

It's doubtful that the number of Vine users, now estimated at about 13 million (not counting any new Kindle Fire downloads) will ever catch up with Instagram's 130 million members, but Twitter is bound to make some inroads if it launches Windows and Blackberry Vine apps before Instagram.

 Meanwhile, the Vine team's post on its blog seems to indicate there's still more to come:

"This is just the beginning. Over the next few weeks, we’ll be introducing some exciting new parts of Vine. As always, we’ll share details on updates as we release them. Follow us at @vineapp to stay up to date."