Perhaps this was mentioned before, but the big Oops with Ping (outside the fact that you can't get rid of it from the sidebar), would seem to be that it's one account, one ping. Unless I'm missing something obvious?
A family of four--mom, dad and the two teens--use one credit card under one account for downloading iTunes. If all four want to set up "pings" for their with their particular circle of friends, focusing on their particular music...they would seem to be outta luck.
From what I can see, one account gets you one Ping under one name.