and what is a 'good' programming language, sir.
Scala (http://www.scala-lang.org/) Clojure (http://clojure.org/) Haskell (http://www.haskell.org/) OCaml (http://caml.inria.fr/)
As much as I dislike it, sometimes PHP is "the right language".
1) I'm guessing (by reading between the lines) that you also haven't "been on the job market", and haven't been plausibly tempted to "jump ship" to any language-purist position?
2) <cynical mode> Just because you haven't set up LinkedIn/FaceBook/Google+ profiles yourself, that doesn't mean they don't all have "shadow profiles" for you based of the social-graphs they've got where your colleagues/friends have "leaked" information about your existence to them and enabled them to infer skills/abilities from them… I don't _know_ that they sell data from "shadow profiles" to recruiters, but I do suspect there's enough money in tech recruitment to make it likely…
Purity doesn't mean moral superiority (although it sounds like) purity means referential purity for example, where the function when called no matter how many times with the same argument returns the same result. That is beautiful because it allows for interesting compiler optimizations, good for testing. Other looser explanations of purity are -- confinement of mutable state (this could mean monads in Haskell modifications to shared global state), immutable data structures in Erlang or Clojure.
Now that said these are all tools. As I mentioned, in practice, a lot of these people in their day job will end up using Java or C++. But the fact that they decided and managed to learn a new paradigm is what is the key.
Heck it could have been data-flow programming or logic programming (Prolog is awesome too, especially when mixed with constraint satisfaction).
Yet another way of putting it, familiarity with these things point to a level of passion and sets someone apart, that is quite desirable. Now, yes, there is a self-referential quality to it all, the more we think functional programming is a proxy for developer quality, the more people will do tutorials just to put it on their resume. Well, then the next fashion will be something else -- quantum algorithms perhaps, who knows.
Single threaded. Concurrency via processes, impossible to share state. And, among the more efficient dynamic languages out there now due to the browser performance race.
There's a slippery word if ever I saw one. Does Java count? Python? C? You could make arguments for all, or none, of these depending on what "proper" is.
Which language doesn't have these options? This could be a description of Bash.
It's practically C and everybody likes C!
Actually, they are compiling to Lua bytecode in this case.
> JS syntax is quite good for I/O
And you can pass around blocks in Ruby.
Once upon a time Javascript was this fragmented language, mostly associated with blinking effects, pop-ups and lame attempts to protect a web page from being viewed as pure HTML. After years of misery the community was tired of how things was and said, "No more"! And so html-tables and javascript was sent to a zip-drive (you probably won't remember those, think of it like a SD-card) to never be seen on the web again.
But evil people who sold out to the dark forces was destined to bring javascript back. By making frameworks they masked the incompatibilities of the language, making it seem like a friend. And the young people who never fought the war, they welcomed this new technology with open arms.
But seriously, we took a typesetting language made for writing documents (just like word) and turn it into a technology for making software. It turned out into a total mess, and now you wonder why taking a language made for manipulating the DOM and using it for manipulating the stack is a bad idea? "When all you have is a hammer..."?
Thad was a tipping point for the web, and the world now is different just because of that.
If you have to choose between power and easiness of development, most people will choose the later, and if I can try a new hardware board that doesn't force me to learn anything new, I'd probably try it.