When blogging first became popular (2003 was the point of take off and by 2006 bloggers had become Time’s person of the year) the fear was that the public sphere would be swamped by trivial, undigested, self-obsessed rantings.
Compared to newspaper or magazine journalism, blogs seemed ill-considered, ill-informed and unaccountable. What was the point of all this chatter?
That was then. We were comparing blogs with what we’d previously known: print journalism. Now, there’s a more favourable comparison. Compared to the semi-public (and barely literate) conversations on social media sites like Facebook (2007’s ‘new new thing’) blogs seem considered, valuable and highly literate. The froth has gone, but there’s something substantial left. Yet rather than being too quick and easy, the criticism now comes from those who find the process of blogging too ponderous, too dull and without an immediate feedback loop.
It’s time to take a fresh look at where blogging stands in the publishing ecosystem, first in terms of ‘immediacy’ and ‘interactivity’. Click to enlarge image.
Next, let’s look at different means of communication in terms of ‘speed’ and ‘reflectiveness’ (a measure of how considered the communications is).
I think this places blogging in a unique position in terms of combining speed with a high degree of reflection. (This rare combination has also been the strength of the traditional diary, reflecting on recent events on a daily basis. Does anyone keep diaries today?)
PR Studies 
I am quite amazed at how many doors blogs have opened for people. Like you said, you would think that people wouldn’t respect them as highly as professional writers and journalists, however it would seem that in a high proportion of situations this is not the case at all.
“the fear was that the public sphere would be swamped by trivial, undigested, self-obsessed rantings” -> Well, it would seem to me that this fear was correct. Fortunately, there are also a lot of very valuable blogs. That, combined with the fact that the less interesting blogs disappear because they do not get enough attention and the writer probably gets tired of his own rantings 🙂 AND the fact that some early bloggers (good or bad) are pulling the plug out of their blog for a various number of reasons, has made the blogosphere far more valuable than some time ago. It certainly has opened doors for me as well, but, like every new phenomenon, blogging has reached a saturation point. Which doesn’t make it less interesting to see where things are going…