Hi I think that the end of the spam and open relays will be when the smtp servers talk only with servers with trust. The bgp approach peering and transit will be ported to a new smtp protocol. Other approach could be the dns system. A central authority that will have registered the stmp servers. This servers could delegate in other servers, etc. I don't know if is out there some draft about a new secure and spam free smtp protocol. But may be interesting for the big players that loose money (Bandwith, servers, staff, etc) accepting spam for their users. my 0.2 € or $ ;) regards, Daniel
Unfortunately, for many of these hosts, there's no motivation to fix things until the collateral damage reaches the equivalent of having a live hand grenade stuffed into an appropriate bodily orifice.
A lot of these are home systems - and the *quickest* way to get them all fixed would be if the 10 top websites refused to talk to them if they were known open proxies.