Riot Games is a pretty big one.
Looking at erlangs site selecting a few:<p>AdRoll 
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TMobile<p><a href="http:&#x2F;&#x2F;erlang.org&#x2F;faq&#x2F;introduction.html" rel="nofollow">http:&#x2F;&#x2F;erlang.org&#x2F;faq&#x2F;introduction.html</a><p>Amazon SimpleDB
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From: <a href="http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;1636455&#x2F;where-is-erlang-used-and-why" rel="nofollow">http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;1636455&#x2F;where-is-erlang-u...</a><p>Also many of the companies using Riak (written in Erlang) also leverage erlang. Some pretty big names use it.<p><a href="http:&#x2F;&#x2F;basho.com&#x2F;about&#x2F;customers&#x2F;" rel="nofollow">http:&#x2F;&#x2F;basho.com&#x2F;about&#x2F;customers&#x2F;</a><p>I would say that Erlang has more than proved itself.<p>One aspect of it is that it is used more of an infrastructure language so not many people see it as glamorous as rushing out to the Go community to brag about their new backend. Its a lot of mature companies that have been around a while and don&#x27;t really need to show off their infrastructure.<p>Also Elixir is gaining momentum (but still a blip) as a very viable language built on erlang.<p>Use what you want and what works.