There was a popular meme on StumbleUpon that played on the addictive nature of the social content discovery service that pointed to two things: millions love it but the dollars were hard to come by for the company. After a decade of trying, it would seem that they’ve finally found their groove.

Since StumbleUpon debuted more than a decade ago, the online bookmarking service has never had its breakout Facebook or Pinterest moment. The startup quietly chugged along with a loyal fan base and steady sales trickle.

StumbleUpon is now profitable and expects to grow revenue as much as 33 percent to $40 million this year, according to the company. More than 20 percent of sales this year are projected to come from applications for smartphones and tablets, Chief Executive Officer Mark Bartels said in an interview.