Ess, C. (2002). Ethical decision-making and Internet research: Recommendations from the aoir ethics working committee. Readings in virtual research ethics. Issues and controversies (p. 1). Retrieved June 16, 2011, from www.aoir.org/reports/ethics.pdf.
The recommendations from the Association of Internet Researchers concerning the ethics of online research. The actual recommendations are pretty slim, but it has a lot of references (some of which I might follow up on), sample consent forms etc.
The first recommendation is to go back to the discipline the study is based in and consider the normal 'offline' approach used in that discipline. I would guess that would place me somewhere around sociology or communication studies. I think this is where Celia Pearce was mentioning feminist ethics as what she had based her study on - I need to go back and check, and also read up on what that framework is!
They also highlight the importance of understanding cultural differences. What are the ethical traditions/legal protections that the participants will be expecting? In fact, large chunks go back to understanding the arena the research is being performed in, and looking at what the participants will expect. They suggest checking both the public statements made about the arena (e.g. privacy statements, and I would guess the EULA would fall into this too), and also noting what mechanisms the system users utilise to indicate they expect things to be more private - e.g. moving to a private chatroom or (in the Rosenberg paper I read a couple of days ago) moving to IM rather than public chat.
They have some nice considerations that I can refer back to, and probably should aim to answer.
One interesting revelation is that the US and the EU have very different approaches to ethics, and these lead to different conclusions. The report basically says that the EU has very stringent laws protecting the privacy of the individual over that of business concerns. The US does the opposite, and protects the business concern over the individual. They call the EU approach deontological, while the US is more utilitarian.