If I asked you to name one of America’s greatest companies, then I would undoubtedly receive a wide range of responses.

Many might say Apple (Nasdaq: AAPL) for the way it transformed our daily lives with its revolutionary mobile devices. Some would choose Exxon Mobil (NYSE: XOM), which generates a staggering $437 billion in annual sales. Still others might point to Walt Disney (NYSE: DIS), an iconic business whose beloved movies, characters and theme parks are enjoyed by millions.

There is no right or wrong answer, merely opinion. The point is to provoke a discussion of which attributes make a company “great.”

Is it popular products? Dominant market share? Colossal sales? Sky-high profit margins?

I, for one, would say none of the above. Let me explain…

#-ad_banner-#In The 1927 New York Yankees baseball team is widely regarded as the best team in baseball history. For decades pundits have swooned over the team’s high winning percentage, massive number of home runs and a whole host of other absurd statistics.

But none of those stats made the team great; they were simply the byproduct of a great team.

The real credit goes to something the other teams that season didn’t have; primarily six hall-of-fame players that included the likes of Babe Ruth and Lou Gehrig. Take those players away and suddenly you’re looking at an average team.

In much the same way, you can’t judge a company’s potential by focusing blindly on operating margins, revenue growth or inventory turnover. These are the byproducts — just numbers pulled from an income statement or balance sheet. Numbers can change overnight.

For example, just a few years ago, RadioShack raked in more than $200 million in profits. Now, it’s bankrupt.

As for today’s hottest products? Well, they just might be forgotten relics tomorrow. You probably remember the floppy disc or the VCR. History is littered with companies (and in some cases entire industries) that came and went. Here’s an item I came across recently that proves the point:

Just like in baseball, the best companies possess something that rivals lack, a “hall of fame” worthy competitive advantage that tilts the playing field in their favor. I’m talking about an economic moat.

At the end of the day, the existence of an economic moat is what separates good businesses from truly exceptional ones. Learning to spot economic moats can mean the difference between mediocre investment returns and leaving a lasting legacy for your children and grandchildren.

In medieval days, wide moats that encircled a castle would help protect the inhabitants from marauding invaders. Today, the same concept applies to businesses with defensive fortifications to help prevent the encroachment of competitors.

The stronger the fortification, the better protected the company and the better the long-term returns for stockholders. That’s why, in the words of Warren Buffett, investors should keep their money in “economic castles protected by un-breachable moats.”

As you can see, the top wide-moat firms have greatly outperformed the S&P over the past decade.

Seeking out products and services surrounded by wide, sustainable moats has been the cornerstone of Buffett’s entire investment philosophy. In fact, he won’t put a dime into a business that lacks a moat. It takes patience, but there is no denying the end result.

That’s because companies surrounded by durable, protective moats are less susceptible to threats from their competition. And that’s exactly the trait I’m looking for when evaluating potential candidates for the “Lifetime Wealth Generators” section of my High-Yield Investing portfolio.

One type of moat I look for specifically is called the Network Effect. This advantage takes hold whenever an increase in the size of the user base increases the value of the service to other potential customers. The bigger the company gets, the harder it becomes for competitors to chip away.

Facebook (Nasdaq: FB) is a prime example. The more people setting up accounts to communicate with friends and family, the more attractive the site becomes to other prospective members. The company now has 1.3 billion registered monthly users and is the most visited website in the world — a fact not lost on advertisers.

But while Facebook has yet to offer its shareholders a dividend, I’ve found a company boasting a yield of 5.7%. It owns and operates the largest cinema advertising network in the country.

And while many forms of advertising are slowly dying, cinema advertising has been growing at a robust 13% annual clip since 2002. That’s because movie-goers recall advertising messages four-to-six times better than television viewers, according to the firm’s investor relations page.

This company’s relationships with America’s top three chains (AMC, Regal and Cinemark), as well as 30 smaller regional groups, allows its network to cover 19,900 screens that are viewed by more than 700 million patrons every year.

And as consumers continue to flock to theaters around the country, this high-yielder is set to continue dominating its market — and growing its payouts to shareholders — for years to come.

Now I can’t give you this firm’s name now — I want to be fair to my subscribers who pay each month to read my premium analysis and learn my top “buy now” picks. But if you’d like to learn more about little-known high-yielding stocks like this one, you can check out my new report “The 4 “Hidden High-Yielders” The Media Won’t Tell You About.” You can access my report by clicking here.