I've been using Tcl fairly quietly since 1998, but am now breaking cover, since I've been developing a product called Sharpen (http://www.passisoft.com/shqa.html ) to help reduce the costs of the "legacy" Vignette/StoryServer sites that use Tcl. There are still a lot of these out there.
The first Sharpen user is Egg plc, the world's largest pure online bank. Egg provides financial services products through its Internet site and other distribution channels.
Sharpen has been in use at Egg since the summer of 2005, and was recently used during the development of its new Egg Money product. Sharpen allowed several serious development and configuration management issues in the StoryServer codebase to be identified and fixed prior to entering the final test cycle, helping the project meet its aggressive timescale.
We have also secured a second reference site in the UK, the media giant British Sky Broadcasting Ltd. BSkyB allowed us to test Sharpen against their codebase at the beginning of the year, and will now be using Sharpen/QA on their legacy code until their port to V/7 is complete.
Version 1.1.3 of Sharpen/QA has just been released, offering improved error reporting facilities and ease of use.
I gave a talk on Sharpen at the small but interesting Fifth European Tcl/Tk Users Meeting - the paper is online at: