From today's New York Times:

No wonder everyone is up till 5 a.m. tweaking their font size and Photoshopping a new icon. At heart, an online journal is like a hyperflexible adolescent body -- but better, because in real life, it takes money and physical effort to add a piercing, or to switch from zip-jacketed mod to Abercrombie prepster. A LiveJournal or Blurty offers a creative outlet with a hundred moving parts. And unlike a real journal, with a blog, your friends are all around, invisible voyeurs -- at least until they chime in with a comment.