As recently as last year, they say that few ISPs actually used filters at the server level to block unsolicited messaging – they left it up to the end user. And the good news for spammers back then was that most end users didn’t bother either.

Now, almost all ISPs use spam filters as blocking, and these get more sophisticated by the day. But the real change ISPs notice is consumers starting to take the problem into their own hands. More are now visiting their ISP's web site to learn about spam filtering and to download the supplied software.