A PythonLanguage, FunctionalProgramming, and ExtensibleMarkupLanguage aficionado who writes two columns for IBM's developerWorks site: "Charming Python" and "XML Matters." The site (http://www-136.ibm.com/developerworks/) is just about unnavigable, so you'll need to use its search facility to find Mertz there.
He also writes for Intel Developer Services, O'Reilly ONLamp, and WebReview.com (DrDobbsJournal).
Visit his own site (http://gnosis.cx/publish/tech_index.html) for almost all of his articles. It's easy to navigate!
Be sure to scope out his "Ramblings on esoteric and flatfooted programming topics" (http://gnosis.cx/publish/tech_index_dw.html). You never know what you'll run into there: a couple papers on MetaClass programming in PythonLanguage, papers on cryptology, a HaskellLanguage tutorial, etc.