Blog and peer reviewing - a little confusion

I would like to signal an interesting article I have found on the web:

Brian Cox is wrong: blogging your research is not a recipe for disaster - by Sarah Kendrew

I tend to agree with Sarah, but I also think some confusion might arise in comparing blogs with peer reviewed articles. So forget peer reviewing and its problems for a moment. We live in a blog here, so I ask the question: what should scientific bloggers do? For instance, should they

- communicate the last minute potentially revolutionary results
- use blogging with the purpose explaining to non specialists how scientists work and what they do
- "teach" to non-specialists the basic foundations of their discipline
- what else?

I don't know the answer; I guess it depends on what you think the purpose of blogging is.

   Cheers Paolo