I think of Erlang as a very specific tool.

Many projects, you could write an initial version in Ruby, Python, Java or whatever, and you're mostly going to be ok, at least while you explore the product/market fit. Maybe you'll have to redo some of it later, but that's likely anyway, so the best approach is to use something that can do a lot of different things reasonably well, and lets you develop quickly.

Erlang always feels to me like it is the best in the world at a few things, and not so good at all for others, meaning it's a bit more dangerous: veer out of its sweet spot, and you're probably better off switching to something else.

Here's something I wrote about it a while back:

http://journal.dedasys.com/2007/09/22/erlang

I also think that Erlang is more along the lines of Smalltalk or Lisp: pioneered some great ideas, but someone's likely to take them and do them in a more palatable format for the masses. Go and Scala, for example seem to borrow some concurrency ideas from Erlang. Node.js is also a "worse is better" competitor which has a huge advantage in terms of the language it uses (Javascript is orders of magnitude more common than Erlang), even if the actual code written for it is not nearly as elegant as Erlang.

Erlang has experienced increased popularity. Yet, it has not experienced the avalanche popularity increase you see with e.g., Ruby or Javascript. I think Erlang is lucky that this has not happened since the community would not be able to keep its current excellent condition if that happened.

Erlangs forte is in a very specific kind of system. If your problem is

* Stateful * Concurrent * State has to "act on its own" * Distributed over multiple machines

Then Erlang is a nice tool for the job.

The language is not particularly old. Note you are not allowed to call a language old if the "newer" language is based on C or its semantics :)

> The language is not particularly old. Note you are not allowed to call a language old if the "newer" language is based on C or its semantics :)

What newer language?

In my opinion

java /c#/ruby/python share little few semantics with c(other then some basic types).

Have you built something cool which fits the bill? I'd love to hear about any successes!

There are plenty of successes out there: Riak, Ejabberd, Whatsapp messenger, Klarna, Demonware, Soundrop, Wooga... Just to name a few

I wonder if those apps run n-times faster on n-cores. I think probably not, due to inherent limitations in the parallelism available in them, but perhaps I should do a study to verify that. Erlang claiming n-times faster on n-cores is snake oil. First of all, not all problems have n-times parallelism in them!

> Erlang claiming n-times faster on n-cores is snake oil. First of all, not all problems have n-times parallelism in them!

I keep reading this claim in Erlang articles, and I wonder why it continues to be made. Its obviously false for the theoretical reason of the limited amount of parallelism in a problem you just stated. It is empirically false on every benchmark I've seen on a real-world architecture (i.e. actual multicore, with actual memory and IO, as opposed to virtual processes). What's strange is that the OP seems to be completely aware of this, but still leads the article with the claim in bold letters before qualifying it later on.

To my mind, Erlang is pretty cool as it is, even before a discussion of multicore performance. But I guess if you "have been waiting 20 years for this to happen, and now it’s payback time" (payback for what?) you are OK with a bit of hyperbole.

I was half of the team that created the instapaper-like functionality on bostonglobe.com using Erlang. It fit the bill perfectly and has run (mostly) untouched since it launched. Features like being able to get a REPL on a production node and quickly add and remove machines from a cluster were quite nice to have.

Sounds like a cool project!

"is it being used in more and more important things?"

Riak is written in Erlang.

Same with CouchDB, which was very fashionable when the article came out.

That was sort of my point -- erlang was fashionable like couchdb, but neither ended up living up to the hype :). In that sense couchdb doesn't count.

We use both Erlang and CouchDB at Cloudant and have great success with both

We use Riak extensively at ideeli. It looks poised to stick around for the long-haul.

I wrote another comment above questioning whether some of the early multicore promises of Erlang have become less relevant with the rise of single-emulated-core VPS servers. That could have dampened the hype.

Also, I'm not an Erlang expert but Erlang does seem to have had a much larger influence than just the uptake of the language. Scala and Clojure have certainly borrowed heavily from it, and that has had a further trickle-down effect into other higher order languages (eg, the actor model).

This is probably a HN phenomenon rather than being Erlang specific. I suspect that as HN ramped up in users, we learned all these great new technologies and now they are 'old' to the community.

Thats why you dont see as many posts about nginx, node, nosql, erlang, haskell, etc. At least not nearly as much as 2,3,4 years ago.

The most popular language I see now on HN is clojure, which tells me a lot about which language stuck with people.