Most book-lovers, I think, have a shelf devoted to their favorite books. It's always half-empty, because those are also the books they lend out when someone asks for a recommendation--oh, you haven't read something by X? Here you go. I love that shelf, even if I rarely lend books: it's where the private activity of reading becomes a shared experience, either through borrowing or via representation: these are the books that have deeply affected me. Maybe they'll affect you, too.
Likewise, there is writing on the Internet that is classic: essays, articles, and fiction that get linked and re-linked over time, in defiance of the conventional wisdom that online writing is transient or short-lived. The Classics are a personal call: what goes on your mental shelf of great online writing won't be the same as mine, and that's okay. This post is a collection of the items that I consider must-reads, accumulated over years of surfing. As I dig stuff out of my memory, I'll keep adding more.