Andrew Sullivan has a long essay in the November Atlantic called "Why I Blog."

My first thought was: How weird to go on about this today. But then: How bloggish of me to think that nothing that could have been said years ago is worth saying today:

Blogging is ... 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.

You end up writing about yourself, since you are a relatively fixed point in this constant interaction with the ideas and facts of the exterior world.... [A] blog, unlike a diary, is instantly public. It transforms this most personal and retrospective of forms into a painfully public and immediate one. It combines the confessional genre with the log form and exposes the author in a manner no author has ever been exposed before....

Alas, as I soon discovered, this sudden freedom from above was immediately replaced by insurrection from below. Within minutes of my posting something, even in the earliest days, readers responded. E-mail seemed to unleash their inner beast. They were more brutal than any editor, more persnickety than any copy editor, and more emotionally unstable than any colleague.

E-mail! You're not truly exposed until you have comments, and Sullivan doesn't, nor does he talk about why he doesn't. (He also doesn't talk about using the blog to enthuse over and over about a political candidate.)

But if you're looking for a long-form essay about blogging -- are you the kind of person who buys a paper copy of The Atlantic? -- this is nicely done.