If you’re Mark Zuckerberg, you’ve got to be thinking about ways of expanding Facebook’s share of people’s time and attention.

Now that the site reaches 65 percent of the American public, and almost 1.4 billion people worldwide, every month, growth can’t just come from getting more people on the platform. It also has to come from increasing each of those people’s usage of Facebook — and from getting more money out of that usage.

But how many status updates do you really need to make, read, like, or respond to?

That’s why the company is dipping its toes into more commerce-oriented arenas. The first step, yesterday, was announcing the ability to send money to your friends via Facebook Messenger. It’ll be coming to the iOS and Android Messenger apps, and Facebook on the desktop, “in the coming months,” Facebook said.

Getting $20 is a damn sight nicer than getting a sticker, so I’d say this has a pretty good chance of success, at least on a small scale. The use cases are intriguing and seem practical enough: paying someone back for a coffee, splitting a check at a restaurant, settling March Madness bets, chipping in for concert tickets, and the like.

Still, it’s a limited rollout. You can only transfer money to friends. You need to have a Visa or MasterCard debit card from a U.S. bank. If you’re mobile, you and your friend have to be using Messenger. Suffice it to say, it’s not a full-blown transaction system.

That’s probably smart, given Facebook’s earlier failures creating commerce systems. Anyone remember Facebook Credits? Facebook Gifts? Didn’t think so. Its biggest success in this arena to date has been processing payments for games and advertisements, to the tune of 1 million transactions per day. (Notably, Facebook didn’t attach a dollar volume to that, so it’s safe to assume it’s a smallish figure.)

Outside parties haven’t fared much better: Witness the Payvment Shopping Mall, which launched on Facebook in 2011 with over 1.2 million products for sale across 200,000 different stores, but then shut down in early 2013.

So Facebook is going to proceed a little more slowly this time, instead of hurtling headlong into another doomed attempt at creating a giant commerce platform all at one go.

The likely next step? I asked Rocky Agrawal, a one-time PayPal employee, former VentureBeat contributor, and all-around payments and retail expert. His bet: Facebook will extend this support to enable people to complete transactions from within advertisements.

“Every click you require users to make is one more chance that somebody will not complete the transaction,” Agrawal said. So instead of clicking through to the advertiser’s site and doing a transaction there, a window could pop up and Facebook could close the transaction via a chat window, without you ever leaving its news feed.

Agrawal also thinks promotion needs to be a big part of Facebook’s strategy. In other words, Facebook needs to get the word out that you can send dollars as well as messages. It has a lot of ways it could do just that. For instance, if someone sends me money, that transaction might be able to show up in both of our news feeds, so other people can see we’re using the Messenger-based payments.

As for me, I’m waiting for the other shoe to drop. When Facebook enables sending payments via Messenger to strangers, not just to friends, then we’ll know that the company is serious about becoming a full-blown transaction platform.

Sending payments to strangers means that you’d be able to use Messenger to buy services and goods, not just from advertisers but from sellers of almost anything.

Facebook would need to put some controls in place to ensure that payments aren’t being used for illicit purposes, or for transactions that are banned on the platform, like gun sales or drug sales.

But it has all the components it needs to build a robust commerce platform.

The question is whether Facebook will pull it off this time — or if Messenger payment will quietly fade away like its previous commerce experiments.