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)
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)