Yes, there are 20 million Stumblers!!

              StumbleUpon reached 20 million stumblers and they are excited for that. Previously, it was just a Firefox extension and now it is into all the browsers, iPhone, iPad and other Androids. It's CEO
Garrett said "When I recently came across a magazine clipping from 2003, it struck me that we now serve as many stumbles in a single hour as we did in our first year of existence! So it’s very exciting for us to reach such a milestone, all from the simple idea of click a button, find cool stuff."

(Source: StumbleUpon)