So, if you all are interested in keeping in touch outside of the SAV site, there are options. These are free or cheap. If everyone decides these are all horrible, I can dig around a bit for alternatives. For background, I worked for what felt like an eternity in IT, so my experience with any of these may color my recommendations.
E-mail based list server (e.g., Mailman)
Pros: easy to use, mostly self-maintained, has options regarding how and when you get messages. Easy to run.
Cons: Only uses e-mail, so no real-time interaction. Not free, but very inexpensive.
Chat-based channel, e.g., telegram.
Pros: free, someone else’s infrastructure, allows some voice and real-time capabilities.
Cons: Not very flexible. No ability to group conversations by subject.
Mastodon instance, probably not connected to the federation.
Pros: Reasonably familiar interface.
Cons: steep learning curve for lazy administrator. 😄 Server required, although a small one would suffice, so not quite free.
Pros: Lots of features. Highly customizable, including voice capability. Very granular security: private channels, trusted-only areas, etc.Cons: Lazy administrator learning curve again for some cooler functions . Would probably require 1-2 volunteers to do moderation in case people get too spicy.