Yahoo!’s recent innovations cover many active fields in technology, including one of the fastest-growing sectors in the business: mobile apps.

Three years ago, Yahoo!’s newly-appointed CEO, Marissa Mayer, decided to shake things up at the company. One of the first things she did was bring new talent onboard. Adam Cahan was one of those talents. Cahan, a graduate of Brown University and a former filmmaker at National Geographic, was chosen by Mayer as Yahoo!’s Senior Vice President of Mobile and Emerging Products. His overall mission is to improve and expand Yahoo!’s global mobile services, such as its apps for mobile and tablet devices, the image and video hosting site Flickr, and Yahoo!’s Smart TV.

When Cahan started his new job in 2012, Yahoo!’s mobile department only had 50 employees in a company of more than 13,000 people. According to him, mobile apps weren’t taken that seriously, or at least seriously enough. “The challenge was that mobile was an afterthought at the time,” he said. “It was, ‘Hey, I have all this work that I need to do and, oh, mobile.’ It was like the finishing part of a sentence as an add-on, rather than a strategy.”

Cahan immediately got to work changing that strategy. First, he expanded his department’s size and increased collaborative efforts in the office. Second, he placed emphasis on user experience rather than profit losses. He instructed his engineering team to simplify and rebuild mobile apps such as Yahoo!’s weather, finance, and email apps, in order to make them more accessible and efficient. Efficiency, in particular, was important to him, as it allows users to get more done and, more importantly, to use the app more often.

This retooling of the mobile department had a profound impact on Yahoo!. Not only has Yahoo! gained more than 400 million new mobile app users since he took over, the mobile department alone grossed an outstanding $1.2 billion in revenue in 2014.

Cahan’s efforts reflect the growing influence mobile apps have on overall technology use. For example, global mobile traffic now represents roughly 13% of Internet traffic. Of that traffic, 80% is done through mobile apps. Global mobile app revenues reached $30 billion last year and is expected to grow from there. Yahoo!’s and Cahan’s emphasis on mobile apps and services is one of the latest innovations the tech industry must get accustomed to.