Blacklists

I have to agree with Phil in that blacklists are a very blunt instrument to deal with spam; however I administrate 60,000 mailboxes and there aren't many better alternatives that are either cheap or enough or scale particularly well. However the vast majority of my users like spam being dealt with transparently; they don't want it tagging or filtering to particular folders in their mail client; they simply don't want to see it at all. So in this regard most high probability spam just gets silently dropped and most users tend to realise fairly quickly when legitimate mail is being lost so I can normally track that down. Currently we silently delete millions of items of spam mail every month and I think it makes a valuable contribution to our users not seeing ads for gambling, penis pills, links to malware, bank account fraud and stock scams. I don't know if blacklisting entire countries is even effective any more as the criminals behind these scams use hijacked PCs all over the world, it's much better to drop mail based on its spam rating rather than its country of origin.