Another day, another community video website. Although, this time, Coull.tv pushes the user-interactive element by asking you to comment on every part of a clip that interests you the most.

If you're watching, say, Will Ferrell's impersonation of the US president, you can comment on anything from Ferrell himself to the horse in the background.

The advantage of so many descriptions - or 'tags' - is that videos will be easier to search for. This may bring Coull.tv out on top in Google searches. The makers of the site are hoping it will encourage greater community feeling as people share titbits of trivia on their favourite videos.

Coull.tv is calling it 'reaction video', and the site is going live today. It has a long way to go before it can steal YouTube's crown, though.