The Registry Update is sent 2-4 times weekly, when new cars are added and existing cars updated. The Update list is managed by Mail Chimp. You can opt-out any time and your email info is kept private. It is an easy way to keep up with Registry additions and updates.
Thunderbird Registry is best viewed on a computer monitor or tablet 640 pixels or wider. There is a lot of information there which is not available on a mobile screen.