I am CEO and Founder of TelEvolution, Inc. a startup with a unique approach to VoIP, in the form of a product called PhoneGnome (see http://www.phonegnome.com ) I served at EarthLink, Inc. for 10 years as Vice President Engineering and Chief Technology Officer. I live in the San Francisco Bay Area and have been using Tcl/Tk for quite a long time. One of my projects is a video-chat, video-presence application that consists of about 30,000 lines of Tcl/Tk code, along with some C and C++: http://www.research.earthlink.net/confmgr/ . Notably, due in large part to Tcl/Tk, the application runs on MS Windows, many flavors of UNIX, and Mac OS X.
Find out more about me at my personal page: http://www.bdt.com/david and my blog at http://mrblog.org .