Also, a lesson for everyone out there: I was about to buy the .co of the domain name but hesitated for a day to ask this question, and it was purchased by somebody else today! Don't hesitate if there's a domain you want.
Always take precautions: http://www.thesitewizard.com/gettingstarted/precautions-to-t...
That said... you don't want a .co .... you want a .com - unless you are selling to developers, you can get away with something else, but for the general public always .com
Vine is used primarily from within apps. If anything, having a .co is a slight helper as their primary target is Twitter where characters are often a premium.
I don't mean this as opposition to you, tmmm, merely that you got me thinking on why one might prefer a .co or be fine without a .com.