Because the majority of the site’s listings are user generated, the community that is Grailed’s strength is also its weakness. The site does almost none of its own fulfillment (the exception is for cases in which it has created editorial content around the items, like its annual Grailed 100, a roundup of influential pieces), and shopping on Grailed is not the frictionless experience many e-commerce retailers have taught customers to expect.

Users describe and label their own products, so finding specific items can require a long trawl through the site. Photos may be professional or night-vision quality. Price negotiations can get heady; shipping rates, self-determined, can be high.

The company does offer buyer and seller protection, but only after claims have been adjudicated by PayPal. Grailed’s team of moderators combs the site for fakes, but even so, complaints of inauthentic products crop up.

And, like any online community, Grailed’s can be fractious.

“They can be a little prickly,” Mr. Metzger said. (Mr. Gupta declined to comment, with a laugh.) But if the virtue of Grailed is democratizing access to designer goods, this comes with the territory. Serving as a hub for the obsessives means weathering the occasional scorn of veterans as well as educating the neophytes.

That education happens not only among the buyers and sellers, but also in the editorial content that Grailed creates: “Master classes” in notable designers and brands from Stüssy to Prada, news briefs, the Grailed 100.