Pinterest, last valued at $11 billion, is expected to make about $169 million this year

Pinterest, the visual social network last valued at $11 billion, is forecast to generate just about $169 million in revenue this year, according to leaked documents obtained by TechCrunch.

But the report said Pinterest's revenue is expected to balloon to $2.8 billion by 2018, as its monthly active users grow from 151 million this year to 329 million over the next three years. The numbers are in line with what the Wall Street Journal reported earlier this year, when it pegged the company's revenue at around $25 million last year, and roughly $3 billion by 2018.

The relatively low revenue figures were somewhat expected as Pinterest only recently started to offer advertising on the site. It's also reportedly working on a new product called "Action Buttons" that allows users to instantly check out shopping items straight from Pinterest. It just recently released a new video-based ad product, as well.

But Pinterest's real value is in its massive user base, which seems to have grown at a healthy pace. TechCrunch says more than half the US women age 18 to 54 have signed up for Pinterest, while its male users more than doubled from last year. It says there are almost 100 million active users on the site, with roughly 60% of new users coming from outside of the US.

In fact, Pinterest has seen the fastest growth in its active user base among all social networks last year, according to this chart by BI Intelligence.

Pinterest is also proving to have strong influence over online shopping behavior, which is a good sign for advertisers to continue to spend money on its platform. According to BI Intelligence, one-third of Pinterest users have bought something online after seeing an item on Pinterest, while more than 75% of the users have engaged in some kind of shopping activity following their time on Pinterest.

All this is proving enough to have investors throw money at Pinterst. Since its founding, Pinterest has raised over $1.3 billion in funding from some of the top VC firms, including Andreessen Horowitz, Bessemer Venture Partners, and SV Angel.