Apple of recent decided to make all the critics of its social network service PING go silent when it upgraded it with music posting features.  This feature has truely raised it's social networking hooks that could make it wildly successful.

Ping now allows users to both post the music they're actually listening to and "like" other music that friends/colleagues/random internet strangers are listening to. It's a simple tweak that's made easily accessible via a sidebar that pops up within iTunes whenever one starts rocking out to a song. Read More
Provided Ping/iTunes can recognize the song in question, the service will immediately ask you whether you want to "like" the track you're listening to—which automatically posts it to your Ping feed without any further input required—or whether you want to post the track to your feed with the option of leaving additional comments to accompany it. That's it.

According to critics, ping has only one problem "it's being locked to iTunes only". However the update done update is a solid first step to revive Ping from its early grave.

From PC Magazine