Almost all the successful non-Google ad networks and exchanges are written in Erlang, Goldman Sachs HFT platform is written in Erlang, several massive scale game platform backends are written in Erlang, several international &quot;national net&quot; banking switches are written in Erlang, a huge chunk of the global land-line and mobile telco switching infrastructure is written in Erlang, Heroku&#x27;s control plane is written in Erlang, GitHub&#x27;s RPC backplane is written in Erlang, Amazon SimpleDB is written in Erlang, Bet365&#x27;s high-scale betting platform is written in Erlang, Pinterest is migrating services to Elixir (rooted in Erlang).<p>There&#x27;s a ton of stuff written in Erlang out there.  A lot of really core infrastructure services that have to just run and run and run.<p>It&#x27;s not particularly trendy, but it gets shit done, and it does so with a quiet dignity. :-)