The preceding link was suggested by avid (if recent) blogger William Gibson. He writes a lot on his blog and I think his commentary on 'real' writing versus bloggin is right on the money.
The purpose of blogging is to not be real writing. There are no compositional principles to employ. In fact I think many blog readers would quickly scan past any real writing occuring on their favourite blog.
That still makes for an interesting new kind of prose, but it is not essays or any other 'slow but careful' kind of writing.

I've found blogging to be excellent for flashes of ideas, and random linkage but poor for synthesizing. I've been working with ideas like that since approx 1988, writing most of the ideas I write down in no more than a page or two of longhand. While very few single entries stand the test of time, even the poor ones end up as important support material for the better ones. The publication of ideas - apart from the obvious vanity factor - adds just a little accountability, and hyperlinks is an obvious opportunity if one likes that kind of thinking.
IF one is to be serious about any of the ideas written down, there is no shortcut around writing it down properly in a longer coherent system.
That's why I hope to reorganize some of the longer running themes here on classy.dk around some more focused essays in the next month or so. These will be versioned slow texts, but on the other hand with a little luck they'll hold some interesting and useful thinking.