Hi Sylvia,
Great to be back on SCoPE, one of my favorite places. For me, there are no ideal numbers. I love to have many people show up for my online courses and classes because it feels like they want to be there. If one or two turn up, it seems like the course/class is not important or more would turn up. Numbers seem to indicate interest. However, that's not always the case.
Sometimes the timing is wrong or people forget to turn up for class. I forget to turn up to so many great live sessions and courses, but I can't be everywhere all at once for now (just kidding). I appreciate when I get reminders to come to live sessions.
I only lurk when I can't find the time to respond. I never lurk in live sessions. I always chat. I love online conversations via chats and discussion forums because I learn so much. I go to live online classes just so I could chat as I listen. I met most of my online friends in chats and discussion forums. I have also met some of my online colleagues at f2f conferences around the world. I have not made friends as a lurker.