For now, they decided to mute all videos that contain copyrighted audio track.

In another words, those funny homemade videos, screencasts, or just any other original that is using a copyrighted audio track would now be muted. Laugh all you want at the dull video that won’t make a sound.

Under all these muted videos, there will be a notice that reads:

This video contains an audio track that has not been authorized by all copyright holders. The audio has been disabled. More about copyright

See it for yourself. Some comments on videos that were muted already, contain NSFW languages, as expected:

©2011 SheepTech

YouTube Mutes Videos with Copyrighted Songs