Noom Walk is a free pedometer app that counts your steps and shares your progress with friends.

Noom Walk is based on software that collects sensor data from the user’s mobile phone. Instead of relying on expensive wearable accessories, Noom Walk utilizes the smartphones users already own. In the future, Noom may explore integration with wearable devices, but for now Noom believes smartphones are sufficient. “We believe that smartphones can do 90% of the work, and you only need dedicated sensors for 10% of use-cases when you really don't have your phone with you,” said co-CEO Artem Petakov.

Unlike much of the mobile technology available now, like the built-in pedometer on the Samsung S4, Noom Walk runs all the time in the background -- yet still uses minimal battery (<3%). You just keep walking, Noom Walk counts passively.

Studies have shown the benefits of walking can be seen from just 30 minutes per day. Walking regularly reduces the risk of chronic diseases like diabetes, cancer, and heart disease. Moreover, research shows pedometer users increase physical activity by about 27 percent, walking about one additional mile per day.

But Noom Walkalso uses social motivation to engage the "desire engine." From the app, you can see the steps your friends have taken, as well as everyone else in the world. The option to comment and high five your friends' step counts keeps users engaged -- there’s no better motivation than knowing you’re all in this together.

To date, beta users have already walked over 40 million steps.