It never really took off and it couldn’t get the Facebook integration it wanted. Back when it launched, Steve Jobs said Facebook had such high demands that they could not reach an agreement and so Facebook was not included as a way of inviting your Facebook friends into Ping.
The new Apple boss, Tim Cook, said on the D10 conference recently that “We tried Ping, and I think the customer voted and said ‘This isn’t something that I want to put a lot of energy into,’”.
With Mac OS X Mountain Lion, to be released in July, Apple is integrating both Twitter and Facebook more heavily into the operating system, making it very easy to share stuff with your friends and followers. One detail though, Mountain Lion is released on July but apparently Facebook integration doesn’t come until October. Oh well, better late than never.