Hi, William and others, I'd like to first express my appreciation for the question of missing data in qualitative and online research and for the excellent responses that make for such good reading and opportunities for thinking on this list. I also offer a few thoughts on the matter. May I first underscore the aforementioned basic tool of triangulation, using other methods of inquiry to supplement whatever ia your primary data collection technique? I don't think this can be overstated, that interviews can add to participant/observation, for example, to give different perspectives. Second, through what people say about each other, data is gained, through the secondary source, even when a person or group may not share that information directly. This information gives a more well-rounded picture than not having access to it at all. Third, we may have to trade off completeness for an in-depth look at some areas. For example, the researcher may know of a splinter group that exists behind the scenes and know from evidence that the influence on the main online community is there. However, without direct access or people talking about it in depth, the researcher may decide to mention it briefly, giving most attention to the main community, All this is predicated on working within what your IRB has approved, of course. -- cheers, andee