Fed up with porn sales spam we located the server by highlighting link. Then we found the upstream providers. Next from a convenience email address we created an address book with the email addresses of every one at the providers- I seem to recall a dozen. Next sending a warning to them like this " Please do not send this crap 'url' to our home computer which is used by our kids" Thankyou.
Sometimes it works but when it doesent we would then cruise the Webmasters ( wankers IOW ) sites and donate the upstream address book to their contacts lists.
We do not get much pornospam these days.
If you think that the client site does not know how to reach the spammers then you are as daft as they think you are. IOW these folks are all of them the SAME people!