I think blog posts from the distant past count! Sei Shonagon, how very awesome you were.

Oh, I am VERY WELL AWARE of the awesomeness of Abelard and Heloise. (Including the fabulousness that was the very first Terrible Celebrity Baby Name. Poor, poor little Astrolabe.) I haven't actually read the letters all the way through, though, so that's definitely something I need to put on my list.