I love to see when a page by posted just by looking at the URL. It also avoids naming collisions. For a static site, not rendered from a db, I wouldn't want to store every post ever written in one dir either. How well does that scale? Yeah, you can probably store 100K files in dir, but it will become unwieldy and slow to load when browsing a lot sooner. Just a dir per year probably solve any such problem.