Are blogs valuable?   They must be to science readers.  A Pew Research Center study shows that Old Media doesn't cover science very well, leaving a gap to be filled by bloggers, with 10X the science content.  And leadership.

They cite the "ClimateGate" East Anglia coverage, which was basically ignored by cheerleaders in science journalism until it took off in the blogosphere.   A week later, it gained traction in traditional media.

Blogs and Traditional Press science coverage

In opposition to non evidence-based claims of Science's crazy old uncle, Donald Kennedy, who clearly misses the glory days of 1980s journalism when it meant progressive good works and claims blogging is just 'journals of announcement', blogs and journalism shared the same lead story with traditional media in just 13 of the 49 weeks studied. 10X the science content and original stuff that journalism doesn't cover until a week later. I'd say blogging is here to stay.