Email is still the preferred and most commmon way of communication between people. Everyone can and knows how to use email.
However for a larger group a mailing list is best, and both yahoo groups and google groups doing the job well, most of the time. It only requires a one time small effort to subscribe and you are done. They are also relatively easy to maintain. I maintain multiple yahoo groups for my club and it is still fine, but occasionally emails get delayed. If I was starting fresh I would probably go with google group instead.
All the other options may be more modern, but either require an app which you otherwise don’t need, or going online to the web to check for messages and reply, or a learning curve, and as such will not work for some folks. Email and email lists are the lowest common denominator.
Someone mentioned phone calls. While this may still work between two people that happen to be free to talk at the same time, I can’t imagine how a phone call can be used for daily club communication.

Ramy