Fake Oakleys may not be fake news, but that has not stopped Facebook from defaulting to market solutions for what it sees as market problems. The problem is that a vast majority of Facebook’s 2.2 billion users experience the platform quite differently from the parties who go there to make money. Facebook, to civilians, is a place that has promised to “connect the world” and, more recently, to “bring the world closer together.” It is a place — like any social network — where people do things they don’t conceive of as competitive. It might not really feel like a digital town square, yet it certainly doesn’t feel like a marketplace.

But quite often it’s managed like one, because in many ways, that’s exactly what it is: a giant, multisided marketplace for buying and selling, in which the largest party — the users — doesn’t do the buying or the selling. A social network’s profitable transactions involve everyone but the users. Ad rates are even determined, in many cases, by auction. If eBay is a machine for finding the right price for a pair of shoes, Facebook — behind the veneer of enabling human connection — is a machine for discovering the right price for a pair of eyeballs. Your eyeballs.

When the biggest platforms seem to be flailing or punting on problems, it’s often because they’re trying to address broad social issues with market solutions. They’re rediscovering, at scale and at great expense to their users, the ways in which a society is more than a bazaar, and the pitfalls of allowing human attention to be sold and resold as a commodity. If a platform is addressing a collective problem in a maddeningly strange way, consider that it might see itself, or only know to govern itself, like an eBay. If it can’t keep bad actors from using the service to exploit other users, that’s because it’s modeled after a system in which finding the highest bidder — or the biggest sucker — is gamely understood to be the point.

There are more lessons for the new internet to learn from the old, and eBay’s more recent trajectory might likewise give us clues about where its successors will go next. EBay was once a world-beating company, destined to totally remake commerce. While its legacy is powerful, it has, over the years, discovered its limits. Amazon, not eBay, is now most synonymous with online shopping. The site has also undergone some more fundamental changes. Auctions, for example, have become less popular over time, as sellers and buyers have favored the site’s other buying styles, with fixed or suggested prices. And in many categories, large sellers have become entrenched, functioning more like stores themselves than desperate participants in a giant open-air market. EBay’s final lesson to the next generation of platforms is that nothing is inevitable. Or lasts forever.

Even still, eBay and PayPal’s alumni are now immensely wealthy and unusually influential, and are using that power to reshape the world around them: Musk, with his electric cars and rockets and flamethrowers; Pierre Omidyar, with his investments and media ventures; Peter Thiel — an early Facebook investor and board member — with his funding of lawsuits against media companies and his eclectic and severe right-wing politics. It is worth considering what sort of initiatives might be spawned by the beneficiaries of today’s much larger platform companies. EBay invited us onto an auction floor and dared us to compete with one another; millions did. Social-media companies found a more lucrative approach, with an even bigger payoff, by building the auction floor right under our feet.