Every other metro gets the argument about whether marketplaces are worth it. Seattle does not need it. Local founders have worked inside the platform, hired out of it, or built their first million on it, and they already know the terms of the trade — the platform owns the shopper and the fee schedule, you own the order and the risk. What is missing is rarely conviction. It is somebody whose actual job is the catalogue: variation structure, suppressed ASINs, backend search terms, buy-box history and the fee report nobody opens.
Two decisions come up here far more than elsewhere. The first is 1P against 3P — a brand with traction in this region gets approached about Vendor Central, and the offer usually gets evaluated on the top-line rather than on chargebacks, price control, co-op allowances and what happens to your margin when the platform sets the retail. The second is fulfilment against product reality. A roaster's entire proposition is freshness, and a bag that spends five weeks in a fulfilment centre before it ships is a listing selling against its own brand. A collectibles or gaming release clears its whole allocation before a fulfilment centre has finished checking the carton in. Neither of those is a bidding problem; both are decided before a campaign exists.
Then the part this agency exists to hold together. We run the owned channel too — the Shopify build, the CRO, the Klaviyo programme — so the marketplace is managed as discovery rather than as a competing business. That means advertising judged on contribution per unit after referral, fulfilment and returns, marketplace pack sizes that do not undercut your own store, and the routes home that the platform genuinely permits: package inserts, Brand Registry engagement tools that reach your followers inside Amazon, and offers built for people who arrive already knowing the product. A pure-play marketplace agency has no reason to care where the second purchase happens. We do.