A disadvantage is the inaccessibility of some of the participants you might want to interview. The time frame for this type of research is more protracted than in FtF interactions. You have to write the email then send it and wait for the response. Working within a group with a variety of computer skills is also challenging to the researcher. Time and patience is instrumental in research of this type.
Qualitative methods are well-suited to the study of electronic communities.
Practice and Activity Theory. The object is to build friendships. I have described this activity as a complex interaction among the individuals, the computer, the community and the norms and behaviors of the community. Usenet interactions are contextually embedded interactions. The computer is a tool mediating human interaction with the world and an actant in that interaction.