Good find - Henk and Hein were actually cousins of my grandfather. His eldest two sons (my uncles) were also involved with the resistance, though this only came out recently.
There are some big places using clojure - the Daily Mail uses clojure heavily for it's website, as do SoundCloud; also, like Scala, it's used internally at some financial institutions - CitiBank have some clojure, and we've been using clojure at IOOF (an Australian superannuation company).
Performance is probably the last thing you need to care about when choosing a programming language for most businesses - unless you are doing hard-core analytics or handling huge scale, you just won't hit the sort of performance problems that are solved by a faster programming language (as opposed to a faster algorithm or architecture).
It really frustrates me that people _still_ put such weight on low level performance. In 1997 I had people saying "don't use Java, it's performance is far worse than C++". It was mostly untrue for business problems then - and computers are many orders of magnitude faster now.
I use truecrypt to encrypt lots of legitimate stuff. All my financial data is on a truecrypt volume on DropBox. And I suspect that folks with something to hide wouldn't find it hard to hide trucrypt itself.
I'm not sure they have the right price point. Many people will impulse buy something of interest for under $10 - psychologically, that's a small amount of money. I bought Louis C.K.'s comedy show for $5, as it's an amount of money I don't mind wasting - it's a small risk.
However at $24, you'll get a number of keen backbone fans - but you won't get all the folks who are interested in backbone, and spine, and ember, and a pile of other frameworks; it's no longer a small enough price for an impulse purchase, so they'll stick to free tutorials.
The same thing applies to lots of other online purchases - I'll buy a vaguely-interesting phone app for $7, but probably not for $15.
The price point where people switch from "cheap as my daily coffee bill" to "the cost of a decent meal" will obviously vary from person to person, and from country to country. But I suspect that $24 is over that point for a lot of people.
(me, I'll probably buy it - but I'll think about it for a lot longer than I would at $5)
brunch (http://brunch.io) provides this for backbone.js / eco / stylus - it merges multiple source files into a single deployable js (and css) file. Or you could use spine, which has this out of the box.
I wonder if there are other possibilities for this? Such as, you could use it to produce print versions of educational videos for distributing to poor rural areas...
"Droving" is admittedly a bit silly - herding probably makes more sense.