VideoSift received Over 100K visits from Stumblers over the past month. Many of them to this post.

And from our stats it appears that Stumblers are the types to hang around and become members as well.

I have used StumbleUpon sparingly. I have the toolbar installed but to be honest I have to be pretty bored to want to hit a completely random site on a press of the button. But when I do use it I find that the pages it brings me to do pique my interest.

We used to have a row of those little "submit to" icons for Delicious, Digg etc - but they just took up room and StumbleUpon is now the only social site icon we use. ;-)