No columnist or reporter or novelist will have his minute shifts or constant small contradictions exposed as mercilessly as a blogger’s are. A columnist can ignore or duck a subject less noticeably than a blogger committing thoughts to pixels several times a day. A reporter can wait—must wait—until every source has confirmed. A novelist can spend months or years before committing words to the world. For bloggers, the deadline is always now. Blogging is therefore to writing what extreme sports are to athletics: more free-form, more accident-prone, less formal, more alive. It is, in many ways, writing out loud.
More here at The Atlantic's site -- and no, this four-page article is not in fact a blog, ironically enough. Still -- it's an eloquent explanation of why, as Sullivan puts it in his extended dek, "it heralds a golden era for journalism."