Karl and I spent some time talking about email again, last night.
Specifically, we were talking about how to deal with filtering and blacklisting spammers. The most recent version of Mailsmith allows you to flag a message and report it to SpamCop. This is a good start, but what would be even better would be pluggable widgets for the various email clients that let you connect to your mail server or ISP -- for the sake of argument, let's say it uses XML-RPC or SOAP -- and a) add a given address to your personal blacklist and b) add a given address or subject to your personal procmail filter. Sadly, I am in no position to write client-side widgets. see also : Whitelist-based spam filtering