1) Howard Rheingold and Neil Postman disagree on the impact of online communities. Rheingold believes they will benefit society, while Postman argues they will have a negative impact.
2) The author conducted research in Second Life and on Facebook to test Postman's theory. In Second Life, users saw it as a real community and spent 2-5 hours daily interacting with entirely different friends than in real life.
3) On Facebook, people interacted more and with more friends online than in person. This supports Postman's view that online interaction threatens face-to-face relationships and real-world communication.