Actually, hovering doesn't reveal the email address in this case. I only see the "Sharing via email only" text, and I can't quite work out what determines wheth

Actually, hovering doesn't reveal the email address in this case. I only see the "Sharing via email only" text, and I can't quite work out what determines whether or not I see an email address, some descriptive text (Google Talk? Google Profiles?), or nothing at all.