TORONTO - StumbleUpon may not have the same household-name cachet as Air Canada, Canadian Tire, Costco or Sears, but online, the Canadian-born social media site trumps them all.

According to Alexa.com, StumbleUpon ranks just inside the Top 100 most-visited websites in Canada and the United States — ahead of all those huge brands and plenty of other big names — even if there are plenty of Internet users who still haven't heard of it.

Not bad for a website that got its start in a Calgary dorm room about a decade ago, and has gradually been built into one of the biggest traffic drivers on the Internet today.

Users of StumbleUpon — of which there are now more than 20 million — are fed a random assortment of web links based on the list of interests they specify, such as beauty, fashion, literature, nutrition, pets, photos, psychology, technology and videos. Users can give a thumbs up or down to each page they "stumble upon," which helps the website build a personalized taste profile.

"The vision was: how do you discover new and interesting content with very little effort?" said co-founder Garrett Camp, 33, who first started the site with Geoff Smith while studying at the University of Calgary.

"Up until about a year ago we were pretty under the radar ... but I think that's changing."

StumbleUpon got a major PR boost last summer when a web measurement company said it had surpassed Facebook in terms of the amount of traffic that its users sent to other websites. Users average about 300 stumbles a month and spend more time on StumbleUpon than they do on Facebook, Camp said.

But he isn't content with the site's success thus far and is eyeing exponential growth.

"I feel like we could be 10 times the size we are now," he said, after listing off a number of features that he hopes will propel StumbleUpon to another level.

Currently, StumbleUpon only caters to English-speaking audiences but that's expected to change sometime this year to help fuel international expansion. Camp also has huge hopes for mobile. He believes StumbleUpon is the ideal time waster for tablet and smartphone users who need just a few minutes of distraction while waiting for something or someone.

"Last year mobile was amazing, we had 800 per cent growth year over year and now it's probably 25 per cent of the overall stumbles —and a year ago it was like three or four per cent, it was a fraction," he said.

"We now see spikes in usage on iPads in the evening and we see a spike in iPhone usage when people are commuting home.

"You can be waiting at a restaurant for someone and just stumble through some cool photos for five minutes, or you can be on your couch at home and just stumble through news articles."

One of the most talked about parts of StumbleUpon's history is how Camp sold the company to eBay for US$75 million in 2007 but then bought it back two years later — reportedly for less than what he sold it for — when it was clear that it wasn't a good fit.

"They made a great offer and they let us be completely independent, so instead of us moving onto (their) campus and immediately integrating the technology it was like, 'You can basically stay in your office, continue doing what you're doing and as you get bigger we can start to use that technology within parts of eBay,'" Camp recalled.

"Over time it's just that we kind of realized when you're in a bigger company things move a little slower, there's a little more process, there's a little more decision-making layers, there's more approvals needed for different things.

"We just kind of realized if we could be independent it would let us be flexible ... and it'd really be the best way to achieve StumbleUpon's potential."