i'd say that has two problems:
1. it assumes personality is static.
2. it assumes the physical world around you is more real than experiences that exist anywhere else. would this extend to phone conversations as well? why are we separating internet conversations? how are internet conversations separate from the rest of a person's life?
internet convo is just simple text, it doesnt really emphasize human emotion. Many people act differently on the net as opposed to real life.
many people act differently depending on the context of the situation and the other people around them anyway.
and text can convey human emotion. it may have some issues, like lack of body language, facial expressions, establishment of tone, etc. but it also has some strengths in terms of being able to clarify your thoughts, which is sometimes difficult to do in real-time conversations in person.