StumbleUpon Activity

  • 8 million total users
  • 35 million pages indexed
  • 10 billion total Stumbles
  • Source: StumbleUpon, Aug. 2009

StumbleUpon is a recommendation engine that helps users discover and share great websites. With over 8 million users, it has become one of the most popular sharing services on the Web today.

About the toolbar

StumbleUpon is a toolbar for Mozilla Firefox that shows recommended websites based on topics the user selects. As users "stumble" through the web and rate what they see, the add-on learns more about their likes and dislikes, and recommendations will improve. With the click of a button, interesting discoveries can be saved to the provided bookmark service, or shared directly with friends.

With over 35 million websites recommended by its users, 500 interest topics, and 10 billion stumbles to date, StumbleUpon has entertaining and educational content for everyone.

Firefox really helped us... it's the best add-ons platform, and 75% of stumbles come from our Firefox toolbar.

—Garrett Camp, Founder & CEO of StumbleUpon
Diagram of StumbleUpon's architecture

How the company got started

Bar graph showing 36 Stumbles per day for Firefox users and 8 for IE Users

Firefox users use StumbleUpon four times more on average than IE users. Source: StumbleUpon

StumbleUpon was founded in late 2001, and developed the first version of its Mozilla-based extension in just a couple weeks. Traditional sharing services require the content creator to embed a widget for each of the various providers a user might want to share through. StumbleUpon's approach was different.

The reason for using an extension is it offers one-click discovery at any time, plus if you came across a new site that you like, you can recommend it to others with a single click.

—Garrett Camp, Founder & CEO of StumbleUpon

Today, that Firefox toolbar has become one of the most popular add-ons, with over 14 million downloads from Mozilla Add-ons and serving over 400 million stumbles each month.

In the last two years, StumbleUpon has tripled its daily downloads, and users are clearly satisfied with their new add-on: 75% of stumbles come from the Firefox toolbar, with an average of 36 stumbles per day.

And because of how well StumbleUpon's recommendation engine knows its users, advertisers can target just users that will find their product or service interesting and relevant. People get to rate these sponsored pages, so that only the best ones get circulated to other Stumblers.

We are a great example of company whose growth was primarily driven by Mozilla Add-ons. Firefox gave us a great platform to build on.

—Garrett Camp, Founder & CEO of StumbleUpon

What's next?

Since its toolbar launch in 2002, StumbleUpon has expanded its reach to web-based stumbling, video discovery, and even URL shortening. Founder & CEO Garrett Camp says we can expect to see a number of new innovations in upcoming months, across its Firefox toolbar and other services.