How To: Two step confirmation

There are at least two approaches in the wiki for two-step confirmation:

How To: Email only sign up -- this is the method first described by Claudio Marai. It is a simple method that allows user account creation with only an email address. The new user is sent a confirmation email with a link. Clicking on that link loads a webpage where they must submit a valid password before their account is marked as confirmed.

How To: Override confirmations so users can pick their own passwords as part of confirmation activation -- is an older, more complex method that accomplishes the same thing.