You're supposed to use g+ communities now. Have you not been following? E-mail based lists you say? pfffff, didn't you hear they're shutting down email and replacing it with 'Babble'?
(Edit: not that I actually think the original comment was inane. Forgot context when I wrote this -- sorry!)
How do you know? I've been told on several occasions that rank is by vote difference (ie up - down).