USB Monitor on iMac

is that possible? video out via USB?

I my old macbook when I rather 2 external displays, one of the video out was through the usb (not powered though). I never did try a usb powered monitor but I would figure there should not be any issues since usb power is a universal concept for many other add ons out there.

Here is an article that reviews a 22 inch one being powered by a 2010 macbook air.

http://9to5mac.com/2012/05/29/review-aoc-1080p-22-inch-displaylink-usb-powered-portable-monitor/