Apple is currently experiencing a number of service outages that it says affects "less than 1% of users." The affected services are iMessage, Photo Stream, Documents in the Cloud, iCloud Backup and iPhoto Journals. From the Apple System Status portal:
Multiple Services - Less than 1% of users are affected Users may be unable to use iCloud Documents, Photo Stream, iPhoto Journals, or Backup & Restore. Users may also be unable to send or download attachments in iMessage.
Thankfully it's isolated to a small number of Apple customers, though it has lasted for around six hours so far. Any kind of outage is frustrating to those it affects, are you one of them?