jaimie parent
They all can be done through Meetup - I think the point here is that multiple channels avoids vendor lock-in and increases the likelihood that a user will overlap with one of the 4 communication strategies.
All of those can be done on meetup - but then we would lose a lot of people who are not, and will not be on Meetup.
The email list is probably the single most important part of the tech stack actually.