For the one or two of you who have commented anonymously, I wanted to let you know I have turned on the Google 'captcha' app. It's quite simple to use. Authors don't have to. I have had a bit of nuisance spamming in the comments and maybe this will take care of them. I am reluctant to require a login.
In any case, as I said, it only affects a couple of people. I would love it if it affected more :-)