Beginning in 2013 with Under Armour’s MapMyFitness acquisition, a number of retailers have acquired health or fitness app companies. Under Armour itself bought two other health apps. And in the past couple years, there have been at least three other retailers that made health app acquisitions, including The Honest Company, Adidas, and Asics.

The Honest Company is an online retailer, Adidas, Asics, and Under Armour have brick and mortar locations all over the world.

While there are many reasons a retailer may want to acquire a digital health company, these deals have largely been driven by a desire for a new marketing channel. Other reasons driving the deals include the opportunity to bring onboard a fully-baked, digital-savvy team or expand on an existing (sometimes fledgling) digital product suite.

Shortly after Under Armour acquired MapMyFitness, MapMyFitness co-founder and VP of Innovation Strategy Kevin Callahan said in an interview that Under Armour would use MapMyFitness data on how users work out and when they work out to help them sell apparel.

Here is a timeline of seven health and fitness app acquisitions by big retailers in the last few years:

November 2013: Under Armour acquired MapMyFitness for $150 million. MapMyFitness, which had about 20 million registered users at the time of the acquisition offered running, biking, and walking apps and social networks that integrated with a wide array of other digital health apps and some 400 devices. The company's GPS-enabled apps, which first launched for Android users in 2007, help users map, record and share their workouts with others on the platform. More

January 2015: Honest Company, an online retailer of eco-friendly baby, beauty and home cleaning products cofounded by Jessica Alba, quietly acquired (or acquihired) Alt12 Apps. San Francisco-based Alt12 is better known by its apps, which in aggregate have been downloaded more than 17 million times: pregnancy tracker and social network BabyBump, women’s social network and health tracker Pink Pad, and parenting social network Kidfolio. More

February 2015: Under Armour acquired two of the biggest health and fitness app makers: San Francisco-based fitness platform MyFitnessPal and Denmark-based Endomondo. Endomondo, which offered free GPS-based tracking apps, went for for $85 million and MyFitnessPal, which created apps that track fitness and diet, was acquired for $475 million. More

July 2015: Gritness, was quietly acquired by Under Armour. Gritness was founded in 2012 and had raised only about $300,000 in seed funding before the deal. At the time the Gritness app was essentially a search engine that helps people find and join workouts. Through the app or website, users can search for workouts or find friends that have similar fitness interests. Businesses can also use Gritness to make their available fitness programs more visible. More

August 2015: Adidas acquired Austrian fitness app and device company Runtastic for $240 million (220 million euros). Runtastic was among those in the early wave of fitness app makers, founded in 2009. Runtastic said it would continue to operate as a brand and an independent business unit out of Linz, Austria, Vienna, and San Francisco. More

February 2016: Boston-based FitnessKeeper, maker of the Runkeeper app, announced an agreement to be acquired by Japanese apparel and running shoe company ASICS for $85 million. More