
According to Engadget HD, Vimeo is now hosting over one million videos, and 10% of those are high-definition. A quote in the article refers to Vimeo as "the largest repository of high-definition video anywhere in the world."
I love that I'm able to upload my HD content to the site, and though it lacks some of the features I dig about competitor site Viddler, the HD feature trumps them all.