Mark -- Two more questions have recently come up with respect to banning domains:

1. Will banning a domain also head off any such messages that are sent to the group's +owner address? 
2. Is it possible to ban a top-level domain? For example, I was able to add *.ru to my list of banned domains, but am unable to verify that it actually works as expected.*

Thanks for any clarity you can provide.

Regards,
Bruce

*Ironically, it also allowed me to ban both *.io and groups.io!