It's my gut feeling that asterisks are so commonly used to indicate required fields that most users have come to understand their meaning. Nevertheless I also like the "optional indicator in the field" idea, and I also agree with the advice in the article to only ask for required fields. In other words, if a field is optional, give strong consideration to omitting it from the form entirely.
If a field is optional, give strong consideration to omitting it from the form entirely.
I totally agree. In that case less is more. You want users to go through a sign up form quickly and be able to get started. You can always provide a settings panel on the other side for adding extra, optional information.
By keeping those fields off the signup form you make things easy and fast for new users.
