I'm sure Facebook is useful for organizing groups and events, but not everyone uses it (yet). I'm not signed up to Facebook (for what I feel have been proved va

I'm sure Facebook is useful for organizing groups and events, but not everyone uses it (yet). I'm not signed up to Facebook (for what I feel have been proved valid reasons over the years), and I feel excluded each time it's required to participate in some event. It's good if organizers can use Facebook as an additional means of organization, rather than assuming it is both necessary and sufficient.