From what I know, the plot does carry onwards and usually the updates are posted on the sites/Discord/etc. I'm sure the offline members will find out from the updates on media and from the members telling it to them as well when they are offline or come back online.
Should you? If you'd like! I think doing that's great communication idea and would allow group members to hop online when everyone else was if they could. I did it before for my groups I had. c: