This option determines what method of registration is used for people wishing to join your forum. You can select from:

• Registration Disabled:
  Disables the registration process, which means that no new members can register to join your forum.
  
• Immediate Registration
  New members can login and post immediately after registering on your forum.
  
• Member Activation
  When this option is enabled any members registering to the forum will have a activation link emailed to them which they must click before they can become full members
  
• Member Approval
  This option will make it so all new members registering to your forum will need to be approved by the admin before they become members.