Bot prevention

[alex]

1. You can use something like this vBulletin modification to require questions for registration:

NoSpam! - an alternative to CAPTCHA images

2. Another thing to consider would be creating a new "Approved Members" group and move all the current Registered Members into that group. Then change the setting to force Moderator Approval for all posts by new Registered Members. Finally, you can use the auto-promotion system to automatically move new Registered Members into the Approved Members group after they have made a certain number of (approved) posts and/or have been registered for a certain number of days.