It doesn’t actually let you change anything in the database, but otherwise it works.
One is the Preview button. When you click it, it shows you a preview of the post you’re working on, formatted as it will appear on the home page. No round trip to the server required.
Another is the expanding/collapsing chevrons. I use those so I can glance at the titles to find the post I want to edit. Then I click the chevron to expand it.
One thing you can’t see: when I submit a new post, the CMS pings Weblogs.com, and I see the text returned from Weblogs.com right there in the page. It’s a friendly little confirmation that the ping worked. Of course, sometimes Weblogs.com reminds it would be a good idea to take a break...