Thank you for having this great resource. I am a new in DNN so may be my question will be too simple to answer. Any way:
There are 5 required fields for registration (User Name, First Name…) is there a way to eliminate “User Name” and “Display Name” by making “Email Address” to become a “User Name” and “First Name” to become “Display Name” as well.

Joseph,
Thank you for answering.

I tried to apply your suggestion for Display Name and it did eliminate Display Name from the registration page but there is two problems:

1. I changed "Display Name Format" to be: Welcome [FirstName], but it doesn't substitute [FirstName] with the real First Name. So I changed it to look like a token: Welcome $(FirstName) but it doesn't work either. It shows the real First Name but instead of welcome put word user at the end.

2. Display name is not changed for previously registered users.

Thank you