There have been a number of problems reported about posting on this blog. This is a template that we (and no doubt millions of others) use run by blogger DOT com. So any issues there are relate to way the software functions and isn't anything we've specifically created!
There is a list of people who are authors and they first and foremost were invited as main contributors by who set it up (me). For those of you who wish to comment (and we like that!) then it seems the software requires you to log in. That makes sense as it will minimise/eliminate comments that are perhaps undesirable!
You may type in a comment but it won't count (and be posted) unless you log in. And if you don't have a login from that drop down list of options.
My suggestion, if you want to comment is:
SET YOURSELF UP WITH A GMAIL ACCOUNT, REMEMBER THE USERNAME AND PASSWORD, POST A COMMENT USING THIS LOGIN AND BOB'S YOUR UNCLE....
If others have an alternative idea please post here as a comment (if you can that is!)