The chart above compares WeHeartIt (blue) with the hypergrowth of Pinterest (purple). Both are successful startups but WeHeartIt is cats and Pinterest is catalogs.

a16z's timing on investing in Pinterest was perfect.

Pageviews for Pinterest plateaued but are now again on the upswing:

From the article:

At one point, WeHeartIt was nearly five times the size of Pinterest. Founded in 2008 by Brazil native Fabio Giolito, the site had 7.7 million uniques and 460 million pageviews in July 2011. At that point, Pinterest had 1.5 million uniques and 91 million pageviews.

Since then, WeHeartIt has remained in the shadows, growing slowly but steadily. Pinterest is now more than twice its size, closing out July with 34.5 million monthly uniques and more than 2 billion pageviews globally, while WeHeartIt hovered at 12.9 billion uniques and 618 million pageviews.

Read more.

WeHeartIt monetizes through self-serve ads:

We've spoken with an investor who tried and failed to invest in WeHeartIt last year. This person said the founder wasn't very interested in taking outside capital. Giolito has a small team that's been content to make money hand over fist from a couple of self-serve ad placements, which are sold at CPMs between $3 and $4. Even if Giolito only sold a fraction of his site's 618 million monthly pageviews at those prices, he'd easily take in hundreds of thousands of dollars a month.