There was a global glitch–40 countries–with iTunes yesterday (an internal DNS error, if you must know) that prevented uses from accessing various parts of the store yesterday. No songs, apps and books could be downloaded.
Before you ask if it this was a North Korean hack, the answer is a firm “no.” Apple admits that this was an issue created by itself.
Someone has done the math and determined that on average, Apple lost $34,246 per minute or $2,054,794 for every hour iTunes is down. Other estimates are as high as $48 million. In 12 hours.