Heard from Pam who asked me to spread the word - TDT is temporarily back up at http://mosquitoes.editthispage.com/discuss
The complete revamp with all archives will happen sometimes after July 1 when Userland releases all the old messages. Over a thousand sites were arbitrarily dumped with no warning whatsoever so at a guess I'd say that whatever else may happen, Dave Winer and his Userland Software Company are toast.
Joseph