For the record: I do not keep logs of visitors who simply read the articles and comments. However, my web server does keep an error log of missing documents and denied requests, for administrative and debugging purposes.
However, I do require an email address for people who wish to post their own comments. This is to establish ownership of the comments; I own only the hosting web server. Of course, I can delete comments if I believe someone is abusing the facility. I can also block access on the firewall, if it’s warranted.