You cannot register for an account using Mailblocks or similar anti-spam service.
When you register for an account, the forum sends an email to you which contains a link you must click before you can post. If you use Mailblocks or similar service, you will never receive your activation email.
The email address you provide for your forum account will only be used for registration, password retrieval, or email notification if you choose to use that feature. 3FC follows a strict anti-spam policy. We never spam or share your address. Period. Your email address is hidden from public view to protect your privacy.