A couple of months ago, I wrote a column saying that most tag-lines used by businesses today were a cop-out. They felt good but promised nothing. A reader wrote and asked if I’d talk about the other side of the coin – what makes a tag-line great?

Creating and using a strong tag-line takes real courage. A tagline that will last for decades is one that makes a bold statement or promise.

So what do you need to consider as you evaluate your tagline?

A strong tagline makes someone take pause. It might be the person it’s directed at, like “Just Do It.” Or it might be the employee who has to keep the promise – “When it absolutely, positively has to be there overnight.“

A memorable tagline should be a bit daunting. That’s what makes it impressive. If BMW had told us its cars were a nice ride, would you have remembered? But who doesn’t want to drive the ultimate driving machine? Talk about setting high expectations!

An enduring tagline is tied specifically to the product or service. Another element of a strong, test-of-time tagline is that we connect it to the company that owns it. We don’t remember it just because it’s clever. We remember who said it. Take this little quiz. Who told us “you deserve a break today” or promised us “we try harder”?

This is where the generic tag-lines about “our people” and quality lose their steam. Who doesn’t believe they provide good quality and that their people are dedicated to their jobs?

A memorable tagline tells a story. In a single sentence, we got the picture when Timex told us “it takes a licking and keeps on ticking.” We can only imagine what might happen if we forgot the warning “don’t leave home without it.”

We learn through stories. We teach lessons through stories. And we buy and sell around stories. It’s much easier for us to remember a story than straight facts. Which is why a storytelling tagline sticks.

A powerful tagline points out how the product or service is unique. Who doesn’t know the unique advantage of M&Ms? They “melt in your mouth, not in your hand,” right? The Marines’ tagline reminds us that they’re very choosy about who they let into their club. “The few. The proud. The Marines.” lets us know that there’s exclusivity to their brand.

Everyone wants a strong tagline, but most businesses are afraid to make a bold promise. What happens if it doesn’t get there overnight? Or if the watch breaks?

Narrowly focused concerns like that lead to ineffective, anyone-could-say-that taglines like “it’s our people.”

Good marketers understand that a tagline is not an absolute. Sure, every once in a while you’re going to miss the mark. But that’s part of the brand promise too. How do you handle it when you fall short?

Smart companies have a well-defined plan in place for how to handle a situation when they haven’t lived up to their brand promise. An “apology” actually can reinforce and amplify the brand promise.

Drew McLellan is Top Dog at McLellan Marketing Group and blogs at www.drewsmarketingminute.com. He can be reached by e-mail at Drew@MclellanMarketing.com. © 2011 Drew McLellan