FYI, if you take a look at the URLs of archived posts, you will notice a path structure based on year/month/day/basename.html.
If you start popping pieces of the path off at the forward slashes, you can see groupings by date. For example year/month/day will give you everything for that day. year/month returns everything for that month, and naturally, including only the year returns every post for that year. Anything else goes back to the main archive for you to navigate.