7 Innovators That Changed Retail Forever These visionaries led their companies against the grain and redefined consumer culture as we know it.

Famed management expert Peter Drucker once said, "If you want something new, you have to stop doing something old." As simple as this advice is, innovative thinking is still the exception, not the rule. So when a company does change the direction of its industry for the better, it's certainly something to celebrate.

In that spirit, I've put together a short list of my retail superheroes -- seven innovators who revolutionized the way people shop. These pioneers weren't necessarily the first in their fields, but they will most certainly be remembered for their willingness to embrace original thinking.

1. Wanamaker's Department Store

Founded in 1877 by John Wanamaker.

"The Grand Depot" was a six-story, Philadelphia retail marvel that housed men's and women's clothing as well as dry goods. Here Wanamaker famously held the first "white sale" and used modern price tags for the first time, making casual shoppers less reliant on salespeople. Wanamaker also established the use of money-back guarantees and newspaper ads to advertise retail goods.

Related: The Fitting Room of the Future Has Arrived

Wanamaker never claimed to have invented the department store, and there were precursors in London, Paris and New York when The Grand Depot opened. But this retailer took the department store trend and pushed it to its modern-day form.

2. The Sears Catalog

Founded in 1888 by Richard Warren Sears.

Originally a retail catalog that sold watches from Redwood Falls, Minn., the Sears catalog quickly developed a reputation for high-quality products and customer satisfaction. As orders increased, the company expanded its line of products and the catalog grew to 532 pages by 1895. That year sales exceeded $750,000 -- what would be more than $21 million in today's currency.

Although Richard Sears wasn't the inventor of mail-order catalogs, he cultivated the medium. For the first time, customers trusted products they couldn't examine in person on an extraordinarily wide scale, an early and obvious precursor to the world of online shopping.

3. Anderson-Little Outlet

Founded in 1933 by Morris B. Anderson. Outlet opened in 1936.

Anderson-Little outlets changed the way we think of outlet stores. Before it arrived, outlets were used to sell excess and damaged goods to employees who worked at the manufacturing factory -- hence "factory outlets." Taking a high-quality men's fashion brand and offering it at a discount price to the public was unprecedented.

The concept of product liquidation became an essential part of every retailer's merchandising plan. Today, daily deal sites such as Groupon and Living Social have translated liquidated products into online sales while sites like Gilt.com feed off of the hype from offering a stylish brand at a deep discount.

4. Wal-Mart

Founded in 1962 by Sam Walton.

Wal-Mart's first location in Rogers, Ark., was called "Discount City" and served as a one-stop shop for almost any product. Today, there are nearly 4,200 Wal-Mart locations in the U.S. alone.

Wal-Mart's innovation not only came from its vast selection of items, but also its wholesale savings in a retail environment. And although Sam Walton and his successors didn't invent the practice of squeezing suppliers on cost, the company took the process to a whole new level. Wal-Mart is an iconic symbol of big box stores and is synonymous with the bottom dollar prices consumers have come to expect.

Related: Built for Business: Midtown Manhattan in the 1920s

5. Apple

Founded in 1976 by Steve Jobs and Steve Wozniak

Founded by modern day tech-idols, Apple has not only revolutionized the way manufacturers distribute their products, but also how complex technology is marketed and sold to the average American. But that's not all.

The company was one of the first mass retailers of digital goods with the release of iTunes in 2002. There were other dabblers at the time, but no one made it as easy to purchase or convenient to consume. For the first time, users could access digital purchases anywhere in the world by logging into an account "in the cloud." The idea of digital ownership had officially arrived.

And Apple's retail innovation is far from over -- some are already predicting its mobile payment system, Apple Pay, will revolutionize the way we shop with our phones.

6. eBay

Founded in 1995 by Pierre Omidyar.

EBay launched as "AuctionWeb" during the dot-com bubble as a consumer-to-consumer online marketplace where people could sell their products with a straightforward bidding system. Online auctions were fascinating to new ecommerce shoppers, and seeing stuff the average person has in their attic sold for cold hard cash inspired a future generation of online sellers.

Later, eBay expanded to include online event ticket trading with StubHub and until recently, it was the parent company behind PayPal, which streamlined online transactions. Today eBay is a multi-billion dollar business with operations in more than 30 countries around the world.

7. Amazon

Founding 1994 by Jeff Bezos.

What sort of retail list would leave off Amazon? This site first attracted consumers with incredible prices on a wide selection of books. For the first time, shoppers could pick up titles they couldn't find at Barnes and Noble while savvy students saved on overpriced college textbooks.

By putting a huge emphasis on customer service, Amazon made sure consumers trusted the site in its infancy, and over time, it has become a one-stop shop for (almost) every ecommerce shopper's needs.

With hard-earned brand loyalty, Amazon can now ask its customers to trust in the company's bold new experiments. Some projects, such as the Kindle, caught on instantly. Some, such as the Fire phone, didn't. But Amazon continues to push the envelope and look for new ways to sculpt the future of retail. Do "delivery drones" ring a bell?

What have I missed?

There have been many more retail firsts -- the first coupon from Coca Cola comes to mind -- that took bold steps away from the norm. But looking back on the history of retail, these seven innovators stand out to me as those who molded our modern expectations of what shopping should be.

Still, it's far from a comprehensive list. So, who are your retail industry superheroes? Share your thoughts in the comments section below.

Related: Why Apple Pay Could Be a Game Changer for Businesses