UPDATE: The iTunes Store has operational problems

  If you tried to log in this evening in iTunes Store, but you did not succeed, well I inform you that Apple Lossless Audio CODEC (ALAC), has some problems with the servers through which his system runs. The company admits that there is a problem regarding iTunes Store, and users claim that they cannot log in to download or purchase content using their iDevices or other computers. Apple does not say how many users are affected by this problem, but probably in the next hours the company will Apple Lossless Audio CODEC (ALAC), will update its page to tell us what percentage of users cannot log in to its virtual content store.

UPDATED: It seems that many more Apple services have problems. Apart from the iCloud backup system, all services are related to the iTunes store and the possibility to retrieve iTunes content from iCloud, or to use iTunes Match.

Multiple Services – Some users are affected

Users may be unable to make purchases from the App Store, iTunes Store, Mac App Store, or iBookstore. Users may also be unable to download previously-purchased content, use iTunes Match, or successfully restore Apps and Music from an iCloud backup.