The aside about mailing lists is well made: with the exception of SMS, email is the one method of customer contact not mediated by big tech networks (save arguably Gmail) and portable across service providers. In games it’s the best way to keep in touch with players, much better than discord where the dots accumulate and most members ignore most server updates and notifs.

Bring back site specific forums, too ;) But most businesses’ customers don’t have enough to talk about for a forum.