People make a lot of money selling eBooks, including to programmers. (Indeed, the recent change in the market is that thanks to the Kindle you can actually do well selling books which don't cost ~$50 and/or fiction.) Ask Amy Hoy, who cowrote a fairly successful one with her husband about JS performance. Your problem is not your pricing. Your problem is that your marketing does not communicate value sufficient to justify a higher pricing.
If you hear someone on HN or demographically similar say "That's too much money!", file them away in the pathological customer bin.
Look at the difference between your site and these sites, then optimize accordingly:
http://javascriptrocks.com/performance/
http://peepcode.com/products/meet-rails-3-i <-- not an ebook, but similar
Part of the problem is the "I don't get something tangible for my money." Never mind you're receiving a lot of, you know, information or anything. People want something they can point to and be like "Yo, I bought that." That's hard to do with eBooks, so you have to consistently price them lower.
Also, marketing to programmers/the HN crowd is significantly harder than a mainstream crowd because you have to deal with the Nick Burns Effect: you are an idiot and I could totally do everything better than you in a weekend. Rails 3 Upgrade Handbook? Received hate mail for weeks about how I should have made it free, how I charge too much, how the book isn't available in HTML, how they could write the whole thing in a weekend using an automated script (seriously), etc. I still get the occasional e-mail about how "I'm probably going to write my own FREE AND OPEN SOURCE guide (which is MORALLY SUPERIOR TO YOURS), so you should just give me a free copy of yours to help you fix any errors." It's a culture issue that's difficult to work around.
Even worse, selling them on something that isn't essential to their job function is difficult (most people don't write eBooks for a living), and the problem with http://authoringebooks.com is compounded with the fact that I'm competing against people who are entrenched and SEO'd out the butt. I don't have time to sit around and tweak my SEO stuff all day, so my organic Google traffic is significantly lower than what it would be if I were more visible.
And also, the market for those who want to write a technical ebook may not be as big as I originally anticipated. :)
So, uh yeah, I agree. Pathological customer bad.
There exist programmers who happily pay $50+ for ebooks. Empirically, there are enough of them to support successful businesses.
P.S. See also consulting rates, writing OSS, etc. After somebody hits my patience for free support I just quote my daily rate at them. If they don't like it, well, enjoy the code.
Haters gonna hate. Ignore em.
Also: I have a kindle, and I use the hell out of it (citeseer!); I'm in no way opposed to ebooks. Just, pricing them is tricky. I've bought several. I also worked in a library for several years. Make what of that you will.
He'd leave books around GT Campus apparently when done with them.
Some categories of programming books whose utility and/or interest needn't drop much years after they were written: Algorithms books (Knuth, Cormen/Leiserson/Rivest/Stein). Books on fundamentals and high-level principles (SICP, Code Complete, Pragmatic Programmer, Design Patterns). Books whose tool-specific content relates to tools that aren't changing much (Paradigms of AI Programming, Thinking Forth) or at least that have a large enough stable-enough core (Effective C++).
(Note: "hasn't lost much value" isn't quite the same thing as "has a great deal of value". Some of those books are better than others.)
I'm not sure if there are many people like me, it's a bit irrational but it's something that might be a good idea to take into account before doing a sale... By doing a sale you fix the value of your product in the mind of the customer to the price of the sale.
Give me a price for the current book including updates in the future and I would gladly pay a bit extra.
Some various problems with eBooks are that 1) you can't resell it, 2) they're difficult to loan to people, or 3) difficult to leave lying around in the office for people to peruse.
That said, I think it's a very, very interesting space and am working on a product myself: http://www.liberwriter.com - I'll hopefully do a 'show HN' in a few days.
I keep saying this: People don't like to pay for eBooks (yet). When I wrote the Rails Upgrade Handbook, I initially put out market feelers at $20, but most people said that was too expensive. I settled pretty arbitrarily at $12. It sold well, but as sales began to slope off, I ran a $6 sale for some time (stated as a celebration of Rails 3 stable I think and then just continued on just because), and wouldn't you know, sales soared for a while. I plan on implementing a pricing structure similar to what he's done here once Rails 3.1 hits next month; we'll see what that experiment yields.
My eBook on writing eBooks (http://authoringebooks.com) hasn't sold well by most mainstream standards, and I can almost guarantee the $49 price tag is partially to blame. Unfortunately, it'd be really problematic to have a print edition of a book on writing eBooks, so I'm just going to have to figure out a better way to market it. :)
Maybe one day soon people will be willing to pay more for eBooks, but at this point I can't blame them. You don't get a tangible good that you can give specific value to. With current rights scehemes, if you delete the file on accident or something, it's possible that you're hosed for good. The medium in general still isn't a solved problem, but maybe one day soon it will be...