preventing spam

[codeshadow]

What Method of registration employed for new members do you guys use or recommend? Lately my forum got full of spammer who spam with porn sites and advertise other products and they sign up with this kind of emails:
[email protected]
[email protected]
[email protected]
[email protected]   
[email protected]
[email protected]
Even some people with hxxp:hotmail.com [nonactive] and hxxp:outlook.com [nonactive]

[margarett]

As usual, the recommendation is to check our wiki page about spam and now to prevent it
http://wiki.simplemachines.org/smf/Spam_-_my_forum_is_flooded_with_spam,_what_can_I_do