This post is a good example, asking whether the approach to feedback mechanisms in climate research has been correct. The drawback? That climate science has become so ideologically polarized that normal scientific exchange is no longer in play.
A second use of blogs, is related and involves the communication of complex scientific ideas in a more generalized form so that non-specialists can understand and appreciate the implications of scientific enquiries.
This post is good example and relates to the same issue of feedback mechanism in climate change.
Finally, a caveat and an answer.
A lot of web material, blogs especially, have a pre-disposed ideology. Some, like this site, outline that ideology: for some it remains implicit and it is left to the reader to filter the message from the dogma. Sadly, there are also web tools that appear to be value neutral, or may be presumed by some to be free of ideology, when they are not. For example, the highly popular wikipedia offers lots of useful information but as an open source resource, it is reflective of the edits of its contributors.
Well now a program has been developed that will at least reveal who has been editing which wikipedia entries: very useful when the topic being edited is subject to radically different ideological interpretations.