David Barnett had a problem.

His headphones would tangle every time he put them in his pocket.

Annoyed, he started to look for a solution, and with none in sight, went to his local fabric store, bought two black buttons and glued them to the back of his phone. Now he could wrap his headphones to the back of his phone instead of putting them loose in his pocket.

His initial "invention" eventually became a product called PopSockets, which is a grip attached to the back of your phone, which allows you to hold your phone easier. It can also be used it as a stand.

Now his company is expected to sell over 60 million units this year alone.

When I got the chance to interview Barnett, I jumped at the opportunity. Here's how I stumbled upon his story, which is itself an illustration of how word-of-mouth product marketing can work for entrepreneurs. 

I met with Leo Friedman, founder of iPromo, for a lunch meeting, and he gave me a custom designed PopSocket that I immediately put on my phone. A few weeks later, I went to interview the CEO of American Marketing Association and former Burger King CEO, Russ Klein. Halfway through the interview, Russ points out that he knows the person who created Popsockets and offered to connect me with him.

The Popsockets grip is literally a walking word-of-mouth marketing machine. 

Here is what I learned from David Barnett about how to bring products to market.

Iteration is the key to innovation.

"I still remember when my friends laughed at me for having these ridiculous buttons on the back of my phone. That motivated me to develop a better version that would earn me more respect," says Barnett.

He started designing and manufacturing every variation he could to get it right. Barnett ended up creating hundreds of variations, with over 60 rounds of prototypes, to find the best product. Making the accordion-like feature was the hardest part, since it hadn't been created before.

Barnett decided to give some prototypes to his students to get feedback on the product. He noticed his students actually used them to grip their phones instead of using it to keep their headphones untangled. That's when he discovered his headphones ideas wasn't the best use case and decided to create a standalone grip.

Barnett iterated from a basic idea of untangling headphones to an idea completely different. Iteration is what got him his success, not an epiphany. 

Launch the product as early as possible, even if it isn't ready for prime time.

After Barnett launched his business in 2014, his friend offered a small section of a booth at a trade show for a few hundred dollars, which Barnett used to give away Popsockets for free.

"Before I knew it, a crowd gathered and my booth quickly became the most popular booth at the show. I had no idea the demand would be so big. The show generated orders of over 20,000 PopSockets. I couldn't believe it, " says Barnett.

The demand for PopSockets was growing by the day, all from word-of-mouth and an initial successful Kickstarter promotion. The demand was almost too much. 

I see many entrepreneurs wait until their product is "ready for prime time," then quickly realize nobody wants it. Barnett wasn't ashamed of his early product, and he was able to get it to market quickly and get great feedback. 

Getting feedback is the core of building a great product, and entrepreneurs shouldn't back down from asking, receiving, and taking action on feedback. Every iteration of the product becomes better than the previous. Don't feel like you have to wait until it's ready, because, in reality, it's never ready.

Your best marketing strategy is to let the product speak for itself.

When Barnett got the small booth at the trade show, his only marketing was that booth. There was no viral, guerilla marketing campaign to drive traffic.

The product was the entire marketing plan.

"Companies love imprinting their logo on the PopSockets because of its prime branding real estate directly on the phone that essentially turns the PopSocket into a mobile billboard. It works great as a branded promotional product, " says iPromo's Friedman.

PopSockets is a great case study of how innovation works, and it should be studied by other entrepreneurs who are creating physical products.

The most interesting part of this story is that Barnett actually found a solution to his headphones problem on YouTube after he created PopSockets. If he looked on YouTube initially, PopSockets wouldn't have been created.

Life can be funny sometimes.