This week the social networking and web exploration site StumbleUpon counted 7 million users. That makes the site nearly 50 percent larger than Twitter, according to ReadWriteWeb‘s analysis.
That’s big news for publishing. StumbleUpon’s Books section taps into those millions of users–rating, tagging, and sharing their favorite literary websites.
Here’s more from the article: “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.”