I thought about it and thought about it and puzzled about it and wrote about it and puzzled about it some more, and finally I decided it's this:
The blog's most defining characteristic is its reverse-chronology. Through its form, the blog insists that what's most important is what's most recently published. The further down the page the reader has to scroll, the more what's there fades in importance. It's like when you do a Google search. When was the last time you looked beyond the first page to find what you were looking for?
Well, I’m now to July 20, and run the very real risk of appearing to be a stalker, but, fuggit, you asked. ;))