I created a couple of empty categories. How to display a list of them? I do not have any items.

Create a main category which holds all subcategories like this:

Main category
--> Sub category 1
--> Sub category 2
--> etc....

Then in the main category configuration at the category view options set to view subcategories.

I was very surprised to receive an email notification informing me of olsen's reply to the above question, because I did not submit the above question - at least not 12 1/2 hours ago, though it is possible that I asked it a couple of years ago.

It seems like my account could have been hacked, because I couldn't login with the old password stored in my p/w manager and had to reset it.

Has anyone else had a similar experience?

Actually the forum subscribes you to certain topics, eg. the ones you opened by default.

I do not think your account was compromised but you can always change your password just to be safe.