Yeah, I have the same story. I have long wanted a "mutable" type system for my HNC project ( https://github.com/kayuri/HNC/wiki, http://code.google.com/p/inv/ ) - it was here on HackerNews about 1 year ago but got little to no interest. I asked on cstheory.stackexchange.com but got no useful answers. And then someone pointed my attention to DDC. I knew about it but I thought it was just an eager revamping of Haskell, just like many other eager haskells (speculative execution etc) out there.