Some reasons why

There is, after all, something simply irreplaceable about reading a piece of writing at length on paper, in a chair or on a couch or in bed. To use an obvious analogy, jazz entered our civilization much later than composed, formal music. But it hasn’t replaced it; and no jazz musician would ever claim that it could. Jazz merely demands a different way of playing and listening, just as blogging requires a different mode of writing and reading. Jazz and blogging are intimate, improvisational, and individual—but also inherently collective. And the audience talks over both.

-- from Why I blog by Andrew Sullivan