It replaced Apple’s MobileMe service, acting as a data syncing center for email, contacts, calendars, bookmarks, notes, reminders (to-do lists), iWork documents, photos and other data.
One of Apple’s iCloud data centers is located in Maiden, North Carolina, US.
Beginning in 2011, iCloud is based on Amazon Web Services and Microsoft Azure (Apple iOS Security white paper published in 2014, Apple acknowledged that encrypted iOS files are stored in Amazon S3 and Microsoft Azure[7]). In 2016, Apple signed a deal with Google to use Google Cloud Platform for some iCloud services.
In October 2016, Bloomberg reported that Apple was working on project Pie which aims to improve the speed and experience of Apple’s online services by being operated more directly by Apple. Also it was reported that Apple was going to relocate all of its services employees to the Apple Campus (1 Infinite Loop, Cupertino, California), as many other employees would be moving to the Apple Park.