I have hundreds of asp.net forms authentication registrations with my old site. Most of the ac_users fields line up nicely so that was nice. But here is what I need for the user import to be even remotely useful for me.
1. Provide a password field.
2. Provide all the address fields.
3. Provide ability to assign imported users to a specified mailing list. This will be used for an "introduction" email. Allow me to send a nice "Welcome to the future of..." message that greets my users to their new home.
The less I have to ask my customers to do, the happier they will be. Kinda reminds me of my ex-wife

As a side note, the users table has fields for secret question and secret answer. Are these even used in AC7 or just maintained for compatibility with the security provider?