What specifically about them do you think is new? I don't know Clojure so I can't judge it, but the idea of "agents" goes back decades, and languages such as Erlang that have been around for a long time have implemented various versions fairly well.<p>Perhaps there is something new, but the space is fairly well covered by lesser-known-but-usable languages, if unheard of in the mainstream. (I use that phrase to draw a distinction against purely academic languages; implementing things there hardly counts.)