I wrote about app integrations a couple of weeks ago - how apps are able to deep link, and put buttons in other apps, making the app ecosystem more like the web.
The first example I showed was Uber, allowing people to order taxis in specific situations. Now I've seen another which shows how apps can pass information to each other in the background.
HealthyNow, an app that tracks your health and sets goals, now integrates with HealthKit in iOS 8 to allow it to pull in data from other health and fitness apps to monitor a bigger picture of your health:
"Through HealthyNow’s intergration with HealthKit, iPhone and iPad touch users can gather the information they choose from various health apps and fitness devices. iOS 8 offers developers the ability for health and fitness apps to communicate with each other. With their permission, each app can use specific information from other apps to provide a more comprehensive way for users to manage their health and fitness.
“Cerner’s integration of HealthyNow with Apple HealthKit adds to an already impressive scale of functionality at the fingertips of our members and will keep Sharp Health Plan at the forefront of mobile health and wellness,” said Michael Byrd, Vice President, Chief Business Development Officer, Sharp Health Plan, which has more than 80,000 members in San Diego County. “Allowing our members’ health and fitness apps to work together and work harder for them in real time instead of after the fact is more convenient, more accurate and consistent with our broader mission to deliver our members’ best health, their way.”"
Update - here is a list of the apps that integrate with HealthKit