Another feature of WordPress 2.6 is that the XML-RPC is turned OFF by default. Now, you have to turn XML-RPC or Atom ON for it to work (in WordPress 2.6, go to Admin’s Settings; Writing; Remote Publishing and check the protocols for ‘Atom’, ‘XML-RPC’, or both).

I’m of a mixed mind of this. On the one hand, a default ‘off’ is a great way to reduce abuses – most people don’t need it, so leaving it off prevents attacks.

XML-RPC (which stands for eXtensible Markup Language Remote Procedure Call) is a powerful way to manage a blog. Using it, you can post articles, comments, read posts and category lists, and more. In fact, it’s really like having about three dozen function calls to your blog – callable from anywhere, by anyone (using your login, of course).

You can see the potential for problems – and in the past, XML-RPC has had its share. So turning it off completely is a good idea for many people.

On the other hand, CHANGING it is problematic – people who are used to it being on (like me) now need an extra step to turn it on, one per blog (and while that doesn’t sound like much, on niche blogs it can add up). As well, if you’re using a remote publishing tool like Microsoft’s Live Writer, you’ll need to turn it on.

My suggestion? Next time, if the blog is upgraded, use the previous assumed setting. And on new blogs, use the safe (new) default. New bloggers are protected, and those upgrading don’t have a new setting to learn.