[X4U] What format does Address Book export for import?

[Robert Nicholson]

So lets say you want to create a bunch of address book entries that  
only have email addresses.

Why can't I use the following format in address book

Email
email at address.com
email2 at address2.com

etc
etc

What is Address Book doing when it validates the file? Is the file  
required to have at least one , or tab delimeter? If so why? Help  
isn't too clear about what the format should look like.