Understand the process of medical research in order to report accuratelyI tend to think of science bloggers as scientists and graduate students - people who either have advanced degrees in the fields they write about, or are pursuing advanced degrees. Then I realised that Brian Switek (Laelaps) is an undergraduate, while Chris Mooney has a B.A. in English (according to his Wikipedia biography). They are two of the most effective science bloggers. So now I have to rethink the demarcation issue. A code of ethics is all the more important when you realise that "science blogger" is both a broader and more narrow term than I had previously thought.
The codes of ethics put forward by Tim O'Reilly and CyberJournalist address some useful issues, but they are (intentionally) broad - they are meant to cover bloggers as a whole. The medical journalist code is more specific. While its target group shares many characteristics with science bloggers, there are notable differences. In general, science bloggers aren't going to be investigative journalists. In addition, their code is probably more narrowly focussed than a science blogger code of ethics should be.