Lukas Kahwe Smith is a partner at Liip. His enthusiasm for the web and open source is only rivaled by his love of ultimate frisbee. He was co-release-manager for PHP 5.3. He is part of the Symfony core team, is co-leading PHPCR and Symfony CMF and has contributed to various parts of the Doctrine project. Basically whatever he manages to fit into his busy life as an ultimate frisbee player.
CMS Content Organization Structures: Trees vs Facets vs Tags
Lukas Kahwe Smith discusses CMS Content Organization structures, comparing Trees to Facets to References to Tags. Running a CMS? You need to read this.