I exchanged a few emails with Dean over the years, and was saddened to learn of his passing in 2018.
He published an early blog called Textism, which was full of wonderful writing (more proof that I love anything with the word “text” in the title). It's largely gone from the web, but the Wayback Machine still holds his hilarious “About” page.
It seems TextPattern is still under active development, and has been since Allen released it in 2003. That puts it up there with Drupal and WordPress in the pantheon of old-school open-source CMS. I used it once and enjoyed it, but that was a long time ago.
Still, it was nice to see it's still thriving, and also nice to be reminded of someone I crossed paths with back when we were making everything up as we went along.