Mark Spencer, American computer programmer and engineer
Mark Spencer (born April 8, 1977) is an American computer engineer and is the original author of the GTK+-based instant messaging client Gaim (which has since been renamed to Pidgin), the L2TP daemon l2tpd and the Cheops Network User Interface.
Mark Spencer is also the creator of Asterisk, a Linux-based open-sourced PBX. He is the founder, chairman and CTO of Digium, an open-source telecommunications supplier most notable for its development and sponsorship of Asterisk. Spencer shifted from CEO to Chairman and CTO in early 2007.