1) Appcelerator Cloud Services (ACS) provides predefined cloud services and APIs that developers can use to add cloud functionality to their mobile apps without having to build their own backend.
2) Popular social apps tend to revolve around common elements like users, photos, checkins, statuses, friends, likes, and reviews. ACS aims to provide these types of services out of the box.
3) With ACS, developers design their app's client interface and logic first before defining the required backend services and data models. They can then use ACS APIs to manage app data rather than having to build their own custom server components.