It's catalog season, the time of year when our mailboxes sag with accumulated paper and retailers nationwide cross their fingers. But even though print continues to dominate the world of presentation, the digital revolution promises to transform the shopping experience.

More than 20 billion catalogs were mailed in the U.S. last year, about a quarter of which were devoted to fashion. Apparel brands mail more catalogs than any other class of retailer - usually between 12 and 24 catalogs each year because as fashionable as, say, maxi skirts are this season, next year no one will want to be wearing them.

Shoppers who strive to stay in vogue have an increasing array of options for keeping up with the Kardashians, whether it's perusing the Internet or their mobile devices. Still, according to Neil O'Keefe, a vice president with the Direct Marketing Assn. in New York, print catalogs remain dominant.

"Customers are on social media, using mobile phones, shopping online, but they're still inspired by the print catalog," O'Keefe said. "Particularly with fashion, the catalog still provides an opportunity to convey your brand. The merchants and their creative teams work extremely hard on the photography for the garment to look as it would in the store."

And that presentation pays off. Roughly $270 billion in retail sales are generated in some way, shape or form by catalogs, according to Paul Miller, vice president of the American Catalog Mailers Assn.

Alluring as print catalogs may be, an increasing number of retailers - Bloomingdales, Nordstrom and J. Crew among them - aren't just mailing them to their customers. They're going digital, showing off this season's lace-trimmed dresses and faux-fur vests in free downloadable apps that mimic the traditional catalog experience, minus the print.

Google Catalogs, Catalog Spree, Catalogue and Coffee Table are among the downloadable apps that have gone live this year, aggregating dozens of catalogs in easily browsable formats. While each app works slightly differently, most encompass home décor and other retail categories in addition to fashion, allowing users to sort catalogs alphabetically or by popularity, category or date added.

"People would rather get catalogs on demand, but they don't want them on a computer," said Joaquin Ruiz, co-founder of the Catalog Spree app that launched in the spring with Nordstrom, Hanna Anderson, Bullock & Jones and other retailers. The app is now accumulating 50,000 new users each month. "Just like Amazon didn't deliver electronic books to the computer screen but to a personal device like the Kindle that mimics the print counterpart, with the iPad, we saw the opportunity to shift catalogs onto a digital platform."

Digital catalogs have existed for years online, but they're rarely used by consumers because page flipping on a screen using a mouse is so unnatural. With the advent of the iPad and other tablets and smart phones that use touch screens, shoppers can flip through pages as they would with print, with an added feature. They can zoom in on specific items and make a purchase through the device.

"Paper and postage costs have escalated to the point that using catalogs is like handing out dollar bills. It's very, very expensive even though the impact of receiving a physical catalog in the mail is tremendously impactful," said Harry Egler, spokesman for the heritage brand Filson, which recently began offering its catalog through the Catalog Spree app.

One in 10 visits to the Filson website is now generated from an iPad or other mobile device, according to Egler. Still, Filson generates a new, 84-page catalog roughly every four weeks, mailing as many as 1 million of them to customers during a peak selling season like Christmas at a cost of $1 per mailing.

"When we send out the catalogs, our phones ring and the Web sales start to come in. We can see and feel the importance of the catalog," Egler said.