Children and preteens are shopping online, and retailers are advertising directly to them. Retailers are leveraging Snapchat, YouTube Kids and other mobile apps to target children and preteens more likely to be on their smartphones, tablets or laptops than watching television. Nine-year-old Isabella Colello described how she shops online and puts items in her cart, which her father can browse through and purchase — or not. “It’s so much better than going to the mall because there aren’t that many places to shop anymore,” she said.

The Washington Post reports that, according to Nielsen, “nearly half of 10- to 12-year-olds have their own smartphones … [and that] by the time they’re teenagers, 95 percent of Americans have access to a smartphone.”

“Kids are shopping on their phones and influencing much more of their families’ spending,” said National Retail Federation director of retail and consumer insights Katherine Cullen. “As a result, retailers are paying a lot more attention to pint-size customers.”

Five Star (which makes binders and folders) and Red Bull just debuted “new back-to-school filters on Snapchat, while clothing chain Justice is advertising in-store fashion shows on its app.” The National Retail Federation estimates that families will spend an average of $685 per household on school-age children in the back-to-school season.

Advocacy groups, however, are concerned, “not just about privacy but also about the kind of influence those ads may have on children.”

“As adults, we might think it’s a little weird or creepy if we’re getting targeted ads that follow us from site to site,” said Campaign for a Commercial-Free Childhood executive director Josh Golin. “Kids, though, are especially vulnerable because they have no understanding of what those ads are or why they’re seeing them.”

According to eMarketer, “nearly 1.5 million children age 11 and under have active Snapchat accounts,” which also predicts “double-digit growth in coming years.”

Although Snapchat requires users be at least 13, this social media platform “has emerged as a holy grail for retailers in search of young consumers,” especially during the back-to-school season when, “last year users spent an extra 130 million hours using the platform.”

Clothing brand Justice presents its mobile app to parents as “a safe place where your girl can create, engage and have fun with awesome girls just like herself.” Preteen shoppers can make wish lists that they are “encouraged to email to their parents.” Amazon also lets children as young as 13 create their own log-ins, but the company “declined to say how many teenagers had signed up for teen accounts since they were introduced late last year.”

“Snapchat and YouTube have become a way for brands to market right to tweens — in fact, it’s one of the only ways to get to them directly,” said Motivate executive vice president of youth marketing Gregg Witt. “If you’re trying to target a specific demographic, TV no longer works. You’re going to mobile, digital, social media.” Direct marketing emails, he added, don’t work because, “if you’re under 16, there’s no way you’re ever, ever checking your inbox.”