Coturnix has surveyed the field and cast down the gauntlet: Science Blogging Should Be Real Science as well as real blogging. It is a fantastic survey of the field (and I'm not just saying that because the Carnival of Bad History got mentioned) and a powerful manifesto for growth and professionalization in the science blog field. I say that, of course, as a non-scientist who reads the science blogs through the filter of Orac, Grand Rounds, and Skeptics Circle (Tangled Bank sometimes), so my view's a bit narrow. I suspect that he's right, but that it's going to be revolution by evolution (fitting, of course) because academic communities are notoriously unresponsive to anything but the most straightforward of stimulus/response inputs.
Which is to say: people will come to blogging for their own reasons (unless it becomes a "good thing" in the tenure/grant calculus) and with any luck we might reclaim a small part of the web to its original purpose: the exchange of scientific and scholarly information in asynchronous accessible discourses.... But it'll take time.
I do think, though, that the carnivals are a great resource; the danger, though, is specialization. Just as nobody reads certain journals except specialists, I'm concerned about carnivals -- quite naturally -- splitting up as they grow in size until they can't be managed or kept track of. What I love about the carnivals now is the cross-fertilization, the window they give non-specialists into new fields and developments and issues. As they become more professionalized, they become less useful in that fashion.
Lots of great stuff to think about.