If you've been having problems seeing the blog today, please try clearing CACHE and all Cookies (at the very least, all those for blogspot.com, blogger.com and booksontheknob.org), then reload the blog. This should fix any problems you may have had with not being able to enter comments.
If you have a blog on blogger, try the above, then go to http://www.blogger.com/home and you should find blogger has been fixed (don't try to get to the admin page for your blog using a saved link, as it seems to cause a redirecting loop, with whatever it is they did to "fix" the login issue earlier today.