I found a PHP code snippet I wrote four or five years ago that allowed me to log IP addresses of website visitors, which I had originally built for providing Dynamic DNS services for an old employer. The code itself was brutish and ugly, but still worked beautifully after all these years. Since I've been working on building up https://www.booksnbytes.net for the past few days, I thought it would be fun to try to make a Wordpress plugin out of it. 3 hours later, and the Quick DynDNS plugin lives! And so, far it does exactly what it did years ago. Check out the bottom of https://www.booksnbytes.net to see what your current IP address is!
Fair warning: I am NOT logging any personal data, nor do I intend to. Yet.