How do it know? WSS 3.0 Table Export

[Doug Ware]

If I export Northwind 2007 to WSS 3.0, the tables, like Customer, that
contain 'Contact' type information get exported to an WSS 'Contact' content
type. Very cool! Now you can view them in Outlook as a contact list.

However, if I craft a table from hand with the exact same name, and the
exact same fields, and export it, it is exported as a 'Custom' content type
and I get no Outlook love.

What magic is done in Northwind to make this happen? I really want to be
able to do the same thing.