Carrying on from MadV's work, the 1globe1world project collects video responses via YouTube, and creates a montage.
In 2006 MadV, a YouTube user, held his hand up to the camera with a word written on it, and encouraged other users to send in video replies. In doing so, he created the 'Most Responded Video of All Time.' This is the result. (via Clive Thompson, Wired)