Evan Schuman's StorefrontBacktalk

No one knows this better than Diapers.com: When you’ve got to go, you’ve got to go. And when you have to shop, you have to shop; there are no exclusions for mobile shoppers without a wireless signal.

Will this ability be valuable to shoppers stranded on airport tarmacs, in wireless deadspots or even in situations where battery conservation is ultra-critical? Diapers.com, which is part of the Quidsi group acquired by Amazon last month, borrowed the offline buying technique from SMS. The mobile app enables the consumer to shop without a signal, although it won’t complete the transaction until a signal is reestablished. It gets darn close, though, with a Diapers.com exec estimating that the “completion” will take 5 to 7 seconds—long enough for a password to be typed and two clicks. But there is a major downside, at least for now: The customer’s offline shopping can’t go beyond choosing previously purchased products.

Beyond the obvious limitations of offering such a short shopping menu, this approach will effectively exclude new shoppers who might be attracted by the offline option. Then again, those people would likely have to have an online connection to create their account.

The company seems to be caught between two extremes, with the prior-purchase limitation or creating a mobile app with a dramatically larger footprint to house all of Diapers.com’s 45,000 SKUs. Josh Himwich, Quidsi’s E-Commerce VP, projects the size of the full product-line version as more than 20 megabytes (a far cry from the regular Diapers.com app, which downloads in three seconds) and adds that the company is seriously prepared to offer it in a future version. Although that size is certainly mammoth by today’s M-Commerce app standard, next-generation mobile devices to be introduced this year should have more than adequate memory.

That larger version, which would presumably wait to download until it detects a nice and fast Wi-Fi or Ethernet connection, “would download the whole catalog and then, once a month, we could hand do updates,” Himwich said.

But why see extremes as the only option? Why not offer a version with the previously ordered options plus a few hundred of the site’s most popular products? Himwich argues that the very nature of Diapers.com’s clientele would make it difficult to find a few hundred products that would please enough of them to bother.

Unlike fans of its grandparent site—Amazon—typical customers of Quidsi’s do not shop there very often. Those sites, Diapers.com plus Soap.com and BeautyBar.com, see their “typical customers” about five times a year, whereas the smaller group of “super customers” shop “sometimes every month,” Himwich said.

Even if those shoppers buy in bulk when they do buy, the universally most popular items may not speak to that many shoppers, he said, referencing the long tail phenomenon.

The ultimate in convenience for those offline shoppers would be to enable the transaction to be completed offline, assuming the consumers had been previously authenticated and registered their payment credentials. But Himwich said security issues are forcing the app to at least do a little online interaction.

“Any time you interact with any account information, you must reverify your credentials,” he said. “A local reverification isn’t a verification. Only the app has verified. We haven’t verified.”