After that, pretty much all you can do is flit around among your friends' profiles, or check your Recent Activity page (click the Ping icon in the iTunes sidebar, or the Ping button in the iTunes Store header to access this page) to see what you're friends have been posting.

There's a lot missing from Ping. For example, what happens when you post something? Your friends can see it in their Recent Activity page, and they can comment on it. But how do you know they've commented, or even liked your posts? There are no alerts, no e-mails, and there's no section on the page that offers a list of what's been commented on. Once your posts are replaced by newer ones, the only way to know if anyone's commented is to keep loading older posts. You can go to your My Profile page, to see just your posts and comments to them, but it's the same problem: if you post a lot, you're not going to want to keep loading older posts just in case someone made a comment.

Ping was , so you could find friends on one service and add them to the other, but this feature was short-lived and vanished after a few hours. So you can't find or invite people you know from Facebook, nor those you follow or who follow you on Twitter.

Part of Ping is meant as a platform for artists to connect with fans, but it's too early to comment on how well this will work, because only a handful of artists were there at launch. There doesn't seem to be any way for users to set up fan pages, but that would be a good way to spur more interaction. You can't post photos, videos, or clickable URLs, so anything you post is limited to remaining within the citadel of Ping.