My name is Jeff Tang, a Phd candidate at National Cheng-Chi University in Taipei. My current research interest is to "hunt" for key users of online communities, thereby elicitationg users' requirements which may improve the Web application development.
        My question encountered is that: one of my research sample (a discussion groups including ASP, ASP.NET, SQL....) has a member over 60,000.
Should I just sample one or two discussion groups? Or, should I investigate all the discussion groups in order to "spot" the most influential users in different discussion groups?
        And, what "important" articles should I study in order to continue my work?
        Thank you very much for your invaluable help.