Pinterest's advertising clients are its sole source of revenue, as of 2015. These programs allow advertisers, such as Gap, to buy Promoted Pins, which are displayed throughout the site within related searches. Like most social media companies, Pinterest is not interested in charging its users directly for services, though other sources of revenue may be explored in the future.
Though relatively new to the scene compared to other social media giants, the company isn't hurting for cash. At the end of 2014, it had already raised $764 million from investors and monetizing content on the site in a greater capacity is a goal. In particular, as noted Ben Silbermann, a co-founder of the site, Pinterest will look to ways to integrate the purchasing of items that are being pinned. This would allow Pinterest to make money as an e-commerce middleman for the retailers that place pins on the site.