After reading chapter four of your book, Personal Connections in the Digital Age, I agreed with the statements you made about online identities. I think communities can be built in both physical locations and virtual location. You talked about shared identities and stated, "The sense of shared space, rituals of shared practices, and exchange of social support all contribute to a feeling of community in digital environments" (p. 86). I think that communities are formed when people are in the same place (shared space), believe in the same ideas (or rituals) and share an exchange to better support the people within the community. I think social media like Facebook is a large community of people that all come together on the same website to converse and socialize.
When you speak of the "lurker" (p. 87) I think this applies to sites like blogs, reviews, or articles. I think it would be false to say that a lurker is the most prominent in sites like Facebook, it would be rare for the majority to only watch others, because Facebook is built on the ideas and shares of others. If the majority didn't post and only read then Facebook would not be as popular as it currently is.
You also talk about Meyrowitz's theory of "no sense of place" (p. 92), and bring up the question of if we are becoming detached from friends and family due to our connections online, rather than physically where we are. I think that for most technology has brought friends and family together. Just as the telephone was a concern of losing our communities or connections, it prevailed and helped more than hurt our society. I think that as long as people can make the switch to a more tech savvy life they will only become more connected to people they love and care about, or haven't even met yet.
Whether your a lurker, or a provider to the internet communities are definitely built within this technological life almost all of us live. We have more information on our hands now, more than ever. People fear things that they are uncertain of, but I think the way that technology has advanced has not only made people more close (maybe not physically) and more informed on endless topics at their fingertips.