Have you noticed that SharePoint doesn’t offer an ability to easily search for people from a mobile device?
Although Office 365 offers an optimized UX for mobile devices, have you noticed that it doesn't offer the ability to search for information?
Although the Client-Side Object Model offers you rich capabilities, there are scenarios when you might need to leverage the SharePoint REST API instead. Find out how to leverage SharePoint REST API in provider-hosted apps.
Remote Event Receivers allow you to integrate your apps with SharePoint by handling events that occur in SharePoint. There are however a few things you should keep in mind before you start working with them.
Even though the App Model doesn’t support deploying declarative artifacts to host web, did you know that you could deploy Custom Actions using the App Model?