Mark Collins suggests how to make a far better sign-up form for your website.
By reducing the number of required fields such as email and password confirmation "“ even usernames "“ the user experience is vastly improved and, consequently, should improve conversions.
Mark uses Twitter as a shining example of these principles. With such a huge audience and user base, they have the statistics to make informed design decisions around these suggestions.
Think about your users, not your personal objectives. Once someone has registered for a website, they can improve their experience with additional data at a later date should they desire.