Apple acquired the app Chomp earlier this year. Chomp was an app discovery platform that allowed users to search through the App Store in a method that differed from Apple's. Apple took the Chomp-style store and implemented it into iOS6 and has now decided to shut down the remaining Chomp business and app installs.
Apple had already killed the Android part of Chomp back in April, shortly after acquiring the service. The iOS app and website remained up and functioning until yesterday's announcement and closing. The Chomp website, http://chomp.com, now redirects to Apple's main website. The app has been removed from the App Store.
What I find really interesting here is the apparent ability of Apple to shut down an existing install of an App. As you see in the picture, Apple effectively disabled the software that was installed on the device, which is a bit scary, if you ask me.
The new Chomp-styled store isn't getting quite the feedback that Apple would like, with many users complaining search and discovery is much more difficult. I tend to agree that the old store format was better.