Short Circuit's Journal: SORBS blocks GMail?

I've been getting messages like these for several days.

This is an automatically generated Delivery Status Notification
 
Delivery to the following recipient failed permanently:
 
    (removed)@(removed).org
 
Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 9): 554 5.7.1 Service unavailable; Client host [66.249.92.172] blocked using dnsbl.sorbs.net; Spam Received Recently See: http://www.sorbs.net/lookup.shtml?66.249.92.172

The strange thing? I tried to send the message using GMail's web interface. I have to wonder how many GMail users are getting bounce messages because of a badly designed DNSRBL...