I am one of the CEOs of the German company terrestris, where I previously was working as developer and project lead. I regularily work with a variety of OSS since my start there back in 2006. Additionally, I am a core developer of OpenLayers, GeoExt and SHOGun. I co-wrote a German book on OpenLayers in 2009 and regularily speak and teach at national (e.g. FOSSGIS) and international conferences (FOSS4G).