How to register and add comments

This morning I have received the following email

I am interested in your new blog on the “Dzhanibekov effect”.How do I register inorder to ask juestions. I live in South East England.
Qusetion:- what is the difference between “inertial reference system” and “inertial laboratory frame”? I guess one tumbles with the object.

After trying to register myself I have found that indeed the procedure was a bit confusing. The server was adding an extra protection against hackers opening a popup window in Polish.
After some internet search and research I have found a way of disabling this protection. So that now the registration should work as follows:

At the bottom of a post there is a place for comments. There you will see:

When you click on “Login to Reply” or “logged” a new window will open

There you can register.

After the registration is completed, you can post comments. Usually first comment is moderated, so it may take a day to appear. Once I see that you are a legitimate user, not an advertising robot or a troll, I take you off the moderation.

I wish the commenting process would be simpler, but my experience shows some protection is absolutely necessary.