Apple’s App Store went down for over 11 hours on Wednesday, alongside iTunes, iBooks, iCloud and even its Mac App Store.

It is the single largest outage Apple has faced, and happened due to an internal issue with its DNS [domain name system].

The economic aspect of this outage has been valued at $25 million in lost revenue. For Apple, this is a few coins dropping out of a $178 billion wallet, but for app developers and musicians, this could mean a big loss in revenue.

“We apologize to our customers experiencing problems with iTunes and other services,” Apple said in a statement. “The cause was an internal DNS error at Apple. We’re working to make all of the services available to customers as soon as possible, and we thank everyone for their patience”.

DNS is the system that links IP addresses to domain names like apple.com. It is not clear why Apple had the internal issue, perhaps moving an IP address on one of its major servers lead to the crash.

Apple iOS App Store is the bread-and-butter of its service revenue, with iTunes continuing to dwindle down in sales from a peak in 2009. When it goes down for 11 hours it is extremely bad for developers that only work on iOS or mobile.

Thankfully, this is not a regular occurrence like PlayStation Network or EA Servers being down, meaning the likelihood of this happening again is extremely low (touch wood). [BetaNews]