Then  you have  the extra  traffic, the  huge amount  of disk  space, the
hassle  of maintaining  the list  of regional  servers when  non-backbone
servers don't have their config  files automatically updated, the privacy
considerations from  the SET CONCEAL clan,  the synchronization problems,
etc. Keeping inverted files is fine (that's what I had in mind actually),
but they must be  decentralized, if for no other reason  than to speed up
non-NETWIDE operations (like DELETE * baduid@somenode).
 
  Eric