It is very interesting why e-mails are not controlled by major players as some use domains to SPAM and some even gmail. Will be in the future some database of users at forums as they abuse forums. Within two days some got 30 SPAM registrations.
As we notice they use profile with URL to SPAM URL's and in the most cases they use URL. If there would be database from Google, Yahoo, BING with SPAM domains, we could import this to forum and 99% will be detected in advance.