I still think Whisper has the biggest Phoenix deployment in terms of traffic. It's a huge part of what makes our web development easy because our backend is all Erlang. Thanks Chris and José (and everyone else) for such a great set of tools.
I'm not actually there anymore, but I know they were moving a lot of stuff to Elixir and Phoenix and some of my friends have given a few talks on it... I went to the last two Elixirconf's but haven't really used it much professionally myself yet. Another media company called Inverse is using Phoenix and Elixir for a lot of their infrastructure. They're still small, but growing rapidly. inverse.com
