Apple's iCloud originally launched in late 2011, as a replacement for the company's MobileMe service.
iCloud, which is designed to allow users to store data from games and music, among other things, lets users sync content between multiple Apple devices. Recently, iCloud has experienced a number of service outages, with the latest occurring this morning.
Article Link: iCloud Boasts 300M Users and 20 Percent Growth in Q2 2013