What do you think about when you think about Walmart?

Maybe you think of Sam Walton, or greeters, or the biggest workforce in the United States.

But when you think about Walmart, do you think about high net worth customers spending thousands of dollars a month?

Maybe you should. Because at its annual shareholders meeting recently, Walmart revealed some surprising statistics about its new personal shopping service, Jetblack, which launched in New York last year.

The key number: $1,500, which is how much Jetblack subscribers spend each month on average, according to the company.  

An internal startup

An independent startup launched from within Walmart's internal incubator, Jetblack's main value proposition is that it will handle shopping from anywhere, responding to texts from customers who pay a $50 a month subscription for the service.

The vast majority of their customers are busy urban moms. Walmart also said two-thirds of its customers engage with JetBlack at least once a week.

Headed by CEO Jenny Fleiss (who previously co-founded Rent the Runway), the startup is on a five to seven-year journey to use Jetblack's "army of human agents to train an artificial intelligence system that could someday power an automated personal-shopping service," as the Wall Street Journal reported.

It's also reportedly a "passion project" of Walmart's head of e-commerce, Marc Lore, according to a former Walmart executive quoted in the Journal.

Part of the benefit

In truth, Jetblack is boldly going where many startups have tried and failed to go before.

Readers of a certain age might remember companies like Kozmo, which tried to do something similar back during the first Internet boom around 2000. But after raising $250 million, the company collapsed.

But Jetblack has no such profit pressures. And Jetblack doesn't even necessarily sell products from Walmart; it will fulfill customer orders from anywhere -- even archrival Amazon.

In fact, you can't even sign up to become a customer without an invitation (although you can join the waitlist.)

That's part of the benefit of launching a startup under the auspices of a $514 billion-a-year retail juggernaut.

It's more of an experiment and a learning experience -- one supported by a company that hopes you might one day think a bit less about greeters when you think of Walmart, and more about affluent customers spending lots of money every month.