From Fedora Project Wiki
Stefan works for the ISP SpeedPartner GmbH in consulting/development as well as engineering. He is active in the Open Source/Linux/PHP-field for several years, also being a speaker at conferences and working as a free author for various magazines. Special focus of his interests are PHP and IPv6.
!SpeedPartner has been contributing to several free projects in various ways, e.g. contributing code/time and also providing one of the official tier1-mirrors for Fedora.
Besides that he is a founding-member and peering-manager for the ISP-association OpenCarrier e.G. .