Sometimes it is useful to mention things that don’t work. Blogger.com (Blogspot) is one of those things that has failed in my experience.
To be specific, I use WordPress for my blog and online ID. Blogger consistently rejects my ID so I cannot post comments on any blog hosted by Blogger. This has been happening for months. Last year I could on occasion remedy the problem by logging out of WordPress and then logging back in. That no longer works. I’ve reinstalled my operating system and use Firefox fully updated. Still no go even with OpenID.
So if you have wondered why I stopped posting comments to your excellent posts and you use Blogger, you now know why.