I have received a couple of emails from people who are having trouble posting to the blog.
Here is how you do it, without registering.
Click comments on the thread.
Go down to comment as.
Scroll down to name/url or anon... If you pick name/url, you can type in screen name or whatever.
After that, captcha should come up.
Just type that into the box and the post should work.
Hope this helps.