What Erlang is good for?

Question

I had not heard about this programming language until I made a research about Whatsapp, a couple of days ago.

So, when I knew about this programming language, it was like...
Why did I never hear about it?
Why is it not popular?

Keep in mind that it was useful for the creation of the third most used social network.

Answer 1

Here's some examples:
https://stackoverflow.com/questions/1636455/where-is-erlang-used-and-why

I'm guessing its not that popular because it's used for very specific needs and not something broad like AI, building applications and created webpages.

Answer 2

One word: Concurrency.
Discord uses elixir, which runs on the Erlang Virtual Machine.

You can read the following articles on how discord scaled to 5 Million users and why it among others use it elxir.
https://blog.discordapp.com/scaling-elixir-f9b8e1e7c29b

#opinion about it's performance
https://content.nanobox.io/discord-elixir-concurrency-template-high-performance/

https://prograils.com/posts/why-discord-pinterest-moz-bleacher-report-use-elixir-case-studies