[jeffbee]

If it wasn't an effective feature for classifying spam, then people wouldn't use it. But, in reality, it's incredibly effective because the only people who want to use residential IPs and rent-a-server IPs for running mailers are criminals and a much smaller population of dorks.

[codegladiator]

I agree lists are definitely effective but its a cat and mouse game sort of with a lot of overhead. We can still use ip lists for accepting/rejecting mail but that should be the lowest priority check with very less weight.

Lists are like the DRM kind of tech, where the genuine user has the real headaches (pay a service to filter my mail, cant self host etc) while the spams are still flowing through.