Ethics vs. Objective Research

This past week we were discussing the issue of ethics in research and being able to conduct empirical research.
I thought this was a very interesting subject, which reminds me of the debates that Clifford Geertz (an interpretive anthropologist) and Marvin Harris (a cultural materialist/positivist) use to have. Both anthropologists would attack each other for the validity of their research. Geertz would take an approach which basically challenged the notion of having an absolutely 'biased-free' ethnography, stating that interpretation was a key component of any ethnography. Harris, on the other hand, promoted the idea that objectivity and an etic approach was fundamental to ethnographic research and that the ethnographer was capable of identifying causal explanations. I think both of them were right in their own way, but mainly this debate can very much be applied to our discussion of ethics and objective research.
On the one hand, we must protect the identity of the human subject, but online, how can we ever make sure we know the true identity of the participant? Should we? How replicable or empirical can research be if you cannot ever validate or replicate or prove the research that is being conducted?
Additionally, online research becomes obsolete very quickly as technologies continue to change. By the time the ethnographer publishes the book, it is very possible that the system is either out dated or not as used any more (like Second Life). Should be move to publishing research online and constantly be updating it, like we do through venues like this blog?