There's an important, longer-term upside for Etsy: In April alone, it won over 4 million new customers and got back 2.5 million others who hadn't used the site in at least a year. (At the start of 2020, it had 46.4 million active buyers and 2.7 million sellers.)

Wall Street has noticed. Shares hit a 52-week low on March 16, coincidentally when the lockdown started in major cities like New York as investors worried about the coming economic downturn. But in the two months since, Etsy shares have risen 157%, making the company worth almost $10 billion.

Silverman admits he was not sure how people were going to behave as lockdowns began. But he thinks people wanting to support independent businesses and buy one-of-kind items—or at least those that are not mass-produced—has a lot to do with Etsy's success.

And the influx of new shoppers has been a rare opportunity for Etsy to wow new customers. "It was important that it be a good experience," says Silverman.

Initial data suggests many are sticking around: Some 32% of new customers who bought a mask last month bought another item within two weeks. And Silverman says on-time shipment statistics and call-center volume suggest the customer experience has been good.

Wall Street analysts seem to agree with the thesis that Etsy will hang on to its new customers once lockdowns end and other retailers reopen their stores. "Even for the existing buyers, they may be exposed to the variety and selection of products available, which could induce them to come to the platform and buy more than just once a year," Deutsche Bank analyst Kunal Madhukar wrote in a research note.

Since Silverman took the helm three years ago, he has sought to professionalize a site that often felt like a flea market. That has included vastly improving its search function—something he says is hard, considering that Etsy sells 60 million unique items at any given time. And occasionally it has meant friction with sellers, either from higher fees or pushing them to offer fast shipping.

But at a time when eBay has floundered and “re-commerce” sites are on the rise, Etsy wants to take advantage of every chance it gets to attract new customers who might not have thought of it much, especially as shopping behavior is in flux.

"For anything you need, the habit for so many people is Amazon, Amazon, Amazon," Silverman says. "If I could just get them to pause for a split second and think to themselves, 'Where else could I get something similar?,' Etsy is going to come to mind a lot of the time."

And millions of mask buyers are now at least more aware of Etsy.