What else is notable about this? If you take a look at our AOL Journals API profile you'll see the API itself is based on APP, the Atom Publishing Protcol (we now have 11 Atom APIs listed and 24 APIs tagged "blog"). More from AOL's Bruce Steinback's announcement post:
AOL Journals has been hosting blogs for AOL users for over four years, with over a million blogs in use.
What can you do with this API? Well, of course you can use Feed Readers as always, but now you can also make additions and modifications to blogs programmatically. So, for example, you can create mashups to write user comments to their AOL Journal and also to other services they may want to publish to, or use AOL Journals as a Container for comments for your mashup.
We've stuck to standards here, extending the Atom protocol (RFC4287), and sticking fairly close to the still evolving Atom Publishing Protocol Draft. It's an entirely REST-style based HTTP protocol, and uses AOL OpenAuth for Authentication. REST is a very straightforward protocol format - you just do a GET, POST, PUT or DELETE HTTP request depending on whether you want to (respectively) read, add, modify or delete content. The content in this case being journals, journal entries or comments, based on the URL you act upon.
AOL has been busy rolling-out open APIs the past year -- we now have 12 AOL APIs in our directory.