Apple says that the iTunes Store, App Store, and Mac App Store are all experiencing disruptions that could prevent them from making purchases on any of the three stores.
From Apple's system status dashboard:
Some users are affected - iTunes Store. Users may be unable to make purchases in the iTunes Store, Mac App Store, and App Store.
The outage has been ongoing since just after 3:00 p.m. ET, and Apple is working on a fix.
Have you been impacted by this outage? Let us know in the comments, and we'll let you know when something changes.
