StumbleUpon Hits 7 Million Users, 50% Bigger Than Twitter

What’s got a button to push, knows how to make money while changing the world and is read all over? StumbleUpon! The social discovery network, like Pandora for webpages and videos, just passed 7 million users according to the site. That’s about 50% bigger than Twitter, though Stumble is rarely talked about and never promoted.