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. Every media personality on the planet is gaga over Twitter.

Today is a good time to remember what a big deal StumbleUpon is, even if it's hardly ever talked about.

StumbleUpon is a Paradigm Shaker

If you haven't used StumbleUpon before, here's how it works. You install the toolbar, identify some categories of content you like on the web, then hit the Stumble button. The service takes you to a web page that is popular with people who share your interests. You've got the option to give that page a thumbs up, a thumbs down or just leave it by hitting the Stumble button again. Over time the service learns what you like and integrates that into the decisions it makes in sending you someplace new when you hit the button.

It's a fun, playful, chaotic way to navigate around the web. The service leverages recommendation technology and the network effects of analyzing large amounts of aggregate user data. Those are two of the most important factors in the emerging era online.

It might feel like a waste of time - but only if you neglect the importance that semi-structured play has in creativity, perspective, socialization and mental health. StumbleUpon is the closest thing that the Web 2.0 world has to brain therapy.

It's Really Popular

StumbleUpon hit 7 million users this week and it can be useful to compare that to Twitter. No one knows how many users Twitter really has, but Google engineer DeWitt Clinton ran some tests last month and estimates it's about 5 million users. A substantial portion of those are accounts populated by spamming robots or people who haven't taken the time to make any friends, which is the point on Twitter.

Meanwhile StumbleUpon has done zero promotion and is nearly 50% than Twitter. Stumble delivers far more traffic to websites than Twitter does and it's learned how to make money. Advertisers pay a few pennies to have their pages inserted into the Stumble streams of relevant users and those ads are silently voted on just like any other page. Silicon Alley Insider estimates the company was making $10 million each year as of this Fall. Of course those profits are landing in the pockets of eBay, who bought StumbleUpon for an estimated $75 million dollars. (There are some rumors that eBay is not happy about the deal anymore and is trying to sell StumbleUpon again).

None the less, we find StumbleUpon just fascinating. Compared to Twitter, it's bigger, drives more traffic and is world changing in different ways - all without any promotion or buzz. Happy 7 million, StumbleUpon, we're impressed.

Amit Chowdry noticed the news and blogged about it first.

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