⚠ Multi-Homing SellersModerate threat

A network effect is strongest when one side is captive to it, and the marketplace's sellers are increasingly not. Listing on Amazon does not stop a seller from also listing on Walmart's marketplace, on TikTok Shop, on Shopify-powered stores, or on Temu¹ — and most now do exactly that. This 'multi-homing' means Amazon no longer monopolizes the seller's attention or inventory, and each rival venue that gains real buyer traffic weakens Amazon's claim to be the only place worth selling.

The danger is that multi-homing erodes the exclusivity that makes a network effect a moat. If sellers are everywhere and buyers can find the same goods on several platforms, Amazon's selection advantage thins and its leverage over sellers — on fees, on advertising, on terms — weakens. The two-sided loop still turns, but it no longer turns for Amazon alone.

The friction runs the other way too: multi-homing costs the seller money and effort, and Amazon remains the venue with by far the most high-intent buyers, which is where sellers actually make their sales. A seller may list everywhere, but if the orders come overwhelmingly from Amazon, Amazon keeps its pricing power over them. Buyer traffic, not seller presence, is the real prize, and Amazon still commands it.

Moderate and slowly building, then. Multi-homing genuinely dilutes Amazon's exclusivity and gives sellers alternatives they lacked a decade ago — but as long as Amazon delivers the buyers, the sellers must come regardless of where else they list, and the network effect holds where it counts, at the point of sale.