I can see why blogs are popular. For the same reason that the Internet in general became popular. Any idiot with a keyboard and a delusion of literacy can suddenly become "published." When the masses put their weight behind the online printing press, they enable an incredible amount of rapid communication but the oft-mentioned signal-to-noise ratio becomes an issue (not that there isn't noise in the print world too).
As a professional freelance writer (albeit part-time - it's like acting or making music, I suppose, only a few of those doing it become rich) I thought the blog might be a nice place to share thoughts quickly, and it is. But I struggle as I begin my blog with the classical nature of the article. In most of my published work, I have to research the topic, make efforts to get facts right, and know too that an editor will see the work before the public does. The concept of a blog seems kind of sloppy to me. It doesn't have to be, and I've seen several impressive technical blogs laudable for their detail, some even including code snippets, graphics, and thorough analysis. The blog of Raymond Chen comes to mind, but I'm not a .Net bigot, it's just an example of what I consider a blog of professional caliber.
I wonder, how much time are people spending writing these blogs? Some of the nicer entries are obviously researched and well presented. Do their writers have a considerably more flexible time schedule or are they simply of remarkable and superior talent?