here’s a new internet retailer on the world’s smartphones, tablets, and PCs. It’s called Facebook.

Last week, Mark Zuckerberg and company started testing a “Buy” button inside the News Feed posts and ads that turn up on the world’s most popular social network, letting users instantly pay for goods and services from other merchants without leaving Facebook. The button provides an added level of convenience for those who spend so much of their time on Facebook already, and it marks the beginning of a new stage in the company’s evolution into a significant money-making machine.

The button should come as no surprise. Inside the company, a man named Nicolas Franchet has long worked as Facebook’s global head of retail and e-commerce. His job is to figure out how to leverage the site’s command of your time and attention to turn it into a place where you shop. As ads have crept into Facebook’s News Feed—scoring the company a dramatic victory in the notoriously challenging realm of mobile advertising—the company has quietly been building in the capacity to take the next logical step: Facebook as an online store that operates unlike another online store. “We can offer a sheer reach that no other platform can,” Franchet said during a press roundtable discussion in San Francisco earlier this year.

From the point of view of a Facebook advertiser, the ads become more useful if they quickly lead from a click to a purchase.

The site’s transformation echoes what’s happening with many other giants of the tech world. Apple, with iTunes and the App Store, is now an online retailer. And Google, with its Google Shopping Express service, is making much the same leap as Facebook, trying to turn ads into more direct purchases. As Amazon becomes more like everyone else, everyone else is trying to become more like Amazon.

This progression only makes sense. From the point of view of a Facebook advertiser, the ads become more useful if they quickly lead from a click to a purchase.

Read more on this story at Wired.