Vringo, a start-up based on the concept of the “video ringtone,” has completed an IPO. The concept is simple and seems like a slam dunk at first sight: attach videos to your contacts so the video plays in lieu of a one dimensional song when they call. Also, direct whichever videos you own and choose to your participating friends’ phones so the videos appear when YOU call. That could be fun. But it begs the question, if the video is playing in your purse or pocket anyway, what’s the point?