Trader Joe’s tiny coolers are selling like hot cakes. Why and how do products go viral?

A few months ago, Thaddeus Yan heard that Trader Joe’s was preparing to sell a fairly mundane new item: A miniature insulated cooler bag. Right away, he was on the lookout. When he went to London on a trip, he even deputized his mom to keep an eye out for the bags.

After months of waiting, Yan drove to a Trader Joe’s at 7:30 one morning this month and bought as many as he could, given the store’s purchasing limit: Two in bright teal, and one in hot pink, both with prominent TJ’s branding. Yan, a social media content creator, paid $3.99 for each of the small bags (too tiny for his Stanley cup, he noted in a TikTok video on his “thaddybearz” account — but big enough for a six pack). Others may not be so lucky. The mini-coolers have already been listed for several times that price on eBay.

Yan is part of a throng of influencers who have been changing, and even accelerating, the way certain retail products go viral. They’re not only rushing out to buy as many items as they can, but spreading the word on their popular social channels, where trends catch fire.

Before social media, it took a lot more for a niche item to hit. “You’d have to see people in public settings,” so trends were much more localized, said Colin Campbell, an associate professor of marketing at the University of San Diego’s Knauss business school. But now “you can have it all happen instantly across the whole country.”

This isn’t even the first time little Trader Joe’s bags have gone viral. In March, shoppers went wild over Trader Joe’s mini canvas tote bags, which rapidly sold out.

Most brands don’t see their products take off this way, especially not twice in a row. On those rare occasions, companies make hay: They talk to fans online and build new marketing campaigns, squeezing as much as possible out of that moment in the sun.

But Trader Joe doesn’t have much of a social media presence. The company staying (mostly) mum has allowed content creators, particularly on TikTok, to fill the vacuum, making the items — which may well have been popular on their own — even more successful. These creators are playing a key role in the worlds of retail marketing.

Talia Heskett, for example, has more than 134,000 followers on TikTok and about 146,000 on Instagram, plus roughly 68,000 on Facebook for her “Trader Joe’s Talia” accounts, as of Friday. Because Trader Joe’s doesn’t boast much of an official online presence, “I’ve kind of taken on that role” with those pages, she said. Heskett is a fan of the grocery chain, and has turned her interest in the brand into something lucrative. Her channels are popular enough for her to earn payment from TikTok.

She’s not the only one posting this type of content. Christy Vetere runs her own TikTok account, “Trader Joe’s and Target Finds,” where she spotlights products from the stores. It had more than 54,000 followers on the social platform on Friday. Heskett, Vetere and others keep shoppers up to date on TJ’s news, tapping into an existing audience of fans to bolster their own followings.

Last March, when TJ’s canvas mini totes went viral, the chain appeared baffled by their popularity.

“What is up with these tote bags? Like, they’re a thing that we didn’t plan for them to be,” said Tara Miller, co-host of the company’s Inside Trader Joe’s podcast, in a March episode. “I’m still a little perplexed about how quickly that excitement went to kind of frenzy,” she said.

“We thought we bought enough of these mini canvas totes to last for several weeks, maybe a whole month,” said Matt Sloan, who hosts the podcast with Miller. “We had no inkling that they would be this exciting, this quickly, for so many customers. We had actually hundreds of thousands of bags come in and go out within a week.”

This time, with the brightly colored coolers, the brand seemed more prepared. “Consider yourself fairly warned: these Totes are totally destined to become the next craze!” screams a product description on the grocery chain’s site.

Apart from the prediction on its website, Trader Joe’s hasn’t said much about the swift-selling seasonal items. A Trader Joe’s representative told CNN that the brand is always looking for new products its customers will like — and that it plans to offer more of the mini insulated bags this summer.

If you search “Trader Joe’s mini insulated bag,” right now you’ll be served a seemingly endless stream of videos featuring the brightly colored items. Some people might just decide to pick one up on their next grocery trip because they saw it online. Others may seek the item out specifically, rushing to stores before they sell out.

“When you can get something that not everyone else has it makes you look cool, makes you look like an insider,” said Jonah Berger, marketing professor at the University of Pennsylvania’s Wharton School and author of “Contagious: Why Things Catch On.”

That desire doesn’t only apply to high-priced or extremely rare luxury items, he noted.

“You often see … trends and things catching on, or going viral, in what I would describe as low-cost public consumables,” Berger said. Think Stanley cups, Owala water bottles and Nike socks — all items that can be seen in public.

These items “can be affordable luxuries, and can allow people to either show their distinction or show that they’re part of a certain group,” Berger added.

For some, the treasure hunt aspect may be part of the fun — especially when it ends not only with the coveted item, but a chance to post evidence of success online.

Yan, who drove to Trader Joe’s at 7:30 am to find the bags, doesn’t run a Trader Joe’s-focused account like Vetere and Heskett. His videos on Instagram and TikTok are mostly devoted to pop culture and Disney. But he likes the chain, and he likes to post about what he buys there.

“You never know what they’re going to drop, it could be some random, really cool thing that everyone might be interested” in seeing, or getting for themselves, he said. “It’s always a surprise.”

The chain’s unusually loyal fanbase is eager for more Trader Joe’s branded merchandise, TikToker Heskett said, but Trader Joe’s doesn’t offer much of that.

“You can’t buy a Trader Joe’s hat, you can’t buy a Trader Joe’s sweatshirt,” she said. That’s why, she thinks, the branded bags have been such a hit. “People want a little piece of Trader Joe’s to carry around with them.”