This reminds me of Ruby on Rails Tutorial by Michael Hartl. I love the idea of the book being online in HTML for free, but you can pay for a better learning experience: screencasts, PDF files, and online training courses.
It reminds me of the same thing, and I think it's a great trend. I wonder why Zed only charges $1 for the PDF/ePub, though. Maybe he doesn't realize how much people are willing to pay? I still sell lots of copies of the Ruby on Rails 3 Tutorial PDF at $26, and I previously sold hundreds of copies at $39. I bet he's leaving a lot of money on the table with his current pricing scheme.
Maybe it's not just about the money? It isn't for me, either. But when the HTML version is 100% free, people have little grounds to complain about the price of an e-book. (Indeed, I've never received a single complaint about the price of any Rails Tutorial product.)
Actually, I researched it quite a bit, and I found I had 300k downloads of the PDF last year, but that 150k of those were from bookmarks into the middle of the PDF. My hypothesis is that 1/2 of the readers want HTML they can bookmark, and 1/2 want to download a PDF. I'm guessing that if I set the price of the download really low, then I'll get more downloads and purchases than just a few hundred.
We'll see how it turns out. I'll be writing about it shortly. Interestingly enough, people seem to be willing to pay $2.99 for an ePub version. I may try doing two prices if that's the case.
I'm one of those poor, unemployed young people for whom the $1 price point was perfect. It's the "What the Hell" price point. The benefit of having it on my Kindle and not having to switch windows all the time is real, but rather small. Perhaps worth $2.99... but certainly not $5.
It's worth more now that I've started getting to know the book of course. I've been reading a lot of programming books for a few months and these examples are substantially superior to anything else I've seen, except for Why's Poignant Guide.
Non-DX Kindle side-tip: Convert .epub to .mobi in calibre with "Text Justification > Linearize Table" checked.
If you don't do this, trying to navigate around the tables on a small screen will drive you batty.
(Still trying to figure out the regex to get rid all the "orphaned" line numbers created by this method.)
Maybe it's not just about the money? It isn't for me, either. But when the HTML version is 100% free, people have little grounds to complain about the price of an e-book. (Indeed, I've never received a single complaint about the price of any Rails Tutorial product.)