[volkadav]

I certainly don't think it's terribly common anymore, but there's still a bunch of stuff out there that uses it. I've seen it most often as a scripting extension to some larger software package (e.g. visual molecular dynamics: http://www.ks.uiuc.edu/Research/vmd/). OpenACS is also built on tcl/aolserver and was an early framework for building community web sites that's still around and still getting updates: http://openacs.org/ The "expect" program is a handy thing to have in your toolkit as an easy way to automate things and is implemented in tcl.

[dalke]

Hey, that's me! I added Tcl to VMD back in the 1990s. :) It lead to my first conference presentation as well.