I've had several folks email me saying that they can't find a link for posting comments. That's kind of weird, but I think I figured out the problem with some help from Larry Seltzer:

Go to http://blogs.msdn.com/login.aspx. Sign in (you'll need a username and password, which are simple to set up. Then go back to http://blogs.msdn.com/johnmont/ and see what happens. You should get a link for posting a comment.