Unable to add ping.fm jabber/xmpp bot to contact list

I'm having problems with the Ping.fm jabber/xmpp bot. I've added it to my roster in pidgin but don't see that I'm authorized to talk to it. I run my own XMPP server and have had a similar problem with someone with an @gmail.com address when I wasn't added to their contact list. Is there anything you can see at your end?