Apple App Store App Review Time
Apple reviews every app submitted to the App Store. New apps and updated apps.
That takes time. Sometimes a long time.
The Apple Developer Support portal tries to clear up things a bit. First you learn about the App Store guidelines. What Apple thinks as a great app. Why app make it or not on the App Store.
Apple App Store App Review Status Information
Then you learn how long it takes for an app review.
Apple provides information for app submissions reviewed in the last 5 business days.
As of September 12, 2014 only 35% of new iOS apps and 53% of iOS app updates have been reviewed.
Looks like the release of iOS 8 is slowing things down. A lot.
You need an Apple developer account to login to the Apple Developer Support portal.