Facebook is a family now, Mark Zuckerberg said onstage today at Facebook’s F8 Developer conference. And he wasn’t talking about Lean In-style camaraderie among his coworkers: he was talking about apps. While Facebook’s flagship app remains its most used, the company has acquired and built a handful of other major social platforms: Instagram, WhatsApp, and Groups among them. But like most families, Facebook has a golden child — and it’s Facebook Messenger.

Since it split Messenger off from the main app last spring, Facebook has gradually laid the foundation for its messaging platform to become the Western world’s answer to Asian giants like LINE and WeChat: mega-messengers that combine communication, gaming, e-commerce, and other categories into a single lucrative channel. It added video and voice calling; it added a way for users to send cash for free; and it hired away PayPal’s well regarded CEO to run the product.

And now it’s a platform: in the biggest announcement of the day, Facebook introduced 47 apps that now integrate natively with Messenger. For starters, Facebook worked with companies that offer enhanced forms of self-expression: there’s Ultratext, for sending flashing neon text GIFs; Camoji, which creates short GIFs using your phone’s camera; and dozens more apps that tweak messages in various ways.

It all seems rather trifling, until you consider the second half of the announcement: you can now message businesses. Companies can integrate Messenger into their websites, allowing customers to complete transactions through the app. They can send order confirmations, shipping updates, and even provide customer support. Presto: Messenger is now an e-commerce platform.

A year ago, the analyst Ben Thompson wrote a post about Facebook and messaging that, in light of today’s news, reads as prophesy. Thompson was trying to make sense of why Rakuten would spend $900 million to acquire a lesser messaging platform named Viber. He sees messaging apps as the successors to direct mail and email: powerful advertising tools that reach customers in a place that feels intimate and personal.

LINE, the dominant platform in Japan and a handful of other Asian countries, helped establish this link by connecting companies with customers through messaging. On LINE you might agree to receive messages from a company in exchange for downloading a pack of stickers. Now that company can tempt you with various offers; LINE has also experimented successfuly with flash sales. (WeChat, the dominant messaging app in China, has employed many of the same tactics, to great effect.)

Is Facebook simply running the LINE playbook? After today’s keynote, I sat down with Chris Cox, the company’s chief product officer. Cox has a habit of understatement, and he characterized the Messenger platform as a kind of research experiment. How big can the platform grow? "We’ll see what people need, and what they want out of it," Cox said. "You learn a lot watching people try to use it."

If it works, though, we should expect Facebook’s other messaging services to develop platform characteristics. Will WhatsApp become a platform, for example? "I think the WhatsApp team will learn from what’s happening here," Cox said. Later, he said, they would decide "what makes sense for them to integrate. We’re just starting with one ecosystem that will allow us to learn."

Writing about Asian mega-messengers last year, Thompson wrote: "the sky is the limit. Both have effectively built platforms on top of iOS and Android and smack dab in the middle of the most meaningful, and thus most-used, part of our lives: our communication and interaction with those we know and care about." Today Facebook has wandered directly into the fray. It may not work as Facebook planned — Messenger’s previous incarnation, as a would-be replacement for email, fizzled — but all the pieces are in place. The golden child is growing up fast.