Windows Phone users are used to 3rd party apps being broken by backend changes. It happens quite often for YouTube and Pandora apps, and it has happened again for MetroTube. MetroTube was just recently updated for WP8, but the party has been crashed by a change in the YouTube backend code. The change makes the app completely useless so they have hidden it in the Store until they can fix the problem.
This same problem has affected all 3rd party YouTube apps. I even noticed it in YouTube+ for Windows 8. The good news is that the devs for YouTube+ were able to find a fix and update the app in less than 24 hours so hopefully MetroTube is able to find a fix equally as fast. LazyWormApps, the devs behind MetroTube, have said that they are working on a fix. The bad news is that unless Google themselves decide to make an official YouTube app stories like this will continue to happen.
[via The Verge]