Today UnDigital launched a platform for buying ad space in packages. The company is a unique adtech startup: it doesn't do programmatic, doesn't offer AI, has no new digital ad formats, and offers no new ads-to-consumers targeting technology. 

Instead, UnDigital calls itself the "industry's first package insert marketplace."

In other words, you buy something. The package comes. And inside is a little 5" x 7" card with an ad.

The company says that "dozens" of retailers have already signed up for the service, citing customers like Barnes & Noble, Saks Fifth Avenue, Land's End, and Lord & Taylor.

It's an intriguing idea.

One reason why: opening a box is almost a little celebration. It's a mini Christmas gift ... even if you know what's inside. While you're in a state of excitement to get your new electronic gadget or boots or T-shirt is probably a pretty good time for another retailer or brand to put a relevant message in front of you.

And it's pretty hard to run afoul of ad fraud, too.

"We guarantee a 100 percent open rate in a digital world where advertisers have grown used to diminishing click-through rates," Ryan Millman, co-founder and CEO of UnDigital, said in a statement.

The keys, of course, will be relevancy and brand protection.

As a brand, you don't want to advertise a competitor, but you're OK with promoting a complementary product: shoeshine for boots, apps for a tablet. And as a consumer, a vastly off-brand and irrelevant ad will probably not hit the mark.

That's probably why UnDigital presents the opportunity as partnering with "complementary brands" to acquire new customers. 

The opportunity is big, and growing. We're buying more online all the time, and more packages are arriving at our doors.

"With billions of packages shipped annually, insert advertising is a greenfield opportunity that the UnDigital marketplace is bringing scalability to for the first time ever," the company says.

With all the digital overload consumers are seeing today, this could be an interesting opportunity for growth marketers.

"While consumers of all ages are reliant on screens, that doesn't negate the power of a piece of paper" said Lisa Malat, VP and Chief Marketing Officer, Barnes & Noble College, in a statement. "In-package inserts distributed via UnDigital's unique platform will aid our ability to capture the college consumer brands covet."