[davidw]

He's talking about dealing with binary data when he says 'binaries':

http://www.erlang.org/doc/efficiency_guide/binaryhandling.ht...

http://www.erlang.org/doc/programming_examples/bit_syntax.ht...

Erlang is really strong for that.

As to Java, sure, you can do anything with it, and do a decent job of it. But sometimes, as a startup, you are resource constrained, so if you can do more with less because you have a good grasp of a tool like Rails, or Erlang or Lua or whatever, that might make the difference. For a large company, Java is definitely a safe pick - no one ever got fired for choosing it: you'll be able to get whatever you need done, and "If we have to think a bit or throw some more kit at it, so be it." For a group like WhatsApp, Erlang seems to have been a good pick.

[rwmj]

I copied my OCaml bitmatch library from Erlang. It's a really great feature of Erlang.

https://code.google.com/p/bitstring/

[cowabunga]

Thanks for the clarification! My bad.

Yes it is far superior from a representation point of view at least there. I have no doubts about that.