Actually we're growing so fast right now that your way of measuring things (active users in the last N days) doesn't help much - most of our total signups occurred very recently - that's just the nature of exponential growth.

As Michael says, a better way to measure the success of a video site is probably how much video people are watching. I posted this mostly just for the fun of comparing us to different countries, not because I think it's the best way to measure our site.