As a programmer who is always expanding my horizons and trying out various technologies (and generally trying to keep my skills fresh), I spent exorbitant amounts of money buying fat tomes full of wisdom that would be obsolete, oh, about 15 minutes after I brought them home. Sometimes, they would already be obsolete, by the time the publisher managed to shove them out the door.
The web changed things... up to a point. I no longer need hefty API references, since most API references are published online, and it is considerably faster to search them electronically. If I have some obscure question about how to accomplish something or solve a problem, there is usually a forum or article somewhere that will address my concern. Still, there is usually at least one good "bible" on any given topic that was worth having. What C programmer doesn't have a yellowing copy of K&R on her shelf? What Perl programmer doesn't have the camel book? What webpage will replace our Stroustrup? Our Knuth?
When I was living in Australia, I couldn't take all my books with me from the States. That was when I discovered O'Reilly's Safari. In the beginning, it was most of the O'Reilly library, online, and you could keep a bookshelf, with a few books on it at a time that you could read on the web. Today, the library has expanded to many publishers, and you can buy a yearly subscription that gives you access to the entire library. The subscription is a bit pricey, but if I truly admit to myself how much I was spending on technical books per year before, the price is not unreasonable. It is access to a giant library of the most recent version of nearly every computer book you could ever want. How do you even put a price on that?
However, like all websites containing technical information, Safari presented an interesting usage-pattern problem for me. I can use a physical technical book without taking up any of my precious screen real estate. An electronic technical book, however, uses your computer screen. If I have a second screen up, I am usually already using it for some kind of work. There is a decent mobile version of the Safari site, but I usually only use it when I'm curious about something on-the-go, because my phone screen is just too small to be a practical display for a tech book. So, if I need to refer to something, I often end up with a laptop to my left or right, displaying a book. This is ultimately a waste of space and energy.
A few weeks ago, I won an iPad in a drawing (Thank you, PayPal!). It arrived yesterday. I thought it was pretty cool, but I wasn't sure yet what on earth I was going to use it for. Before the day was out, I was already browsing a tech book on my iPad, while I coded on the desktop. Well, now, there's a perfectly good practical use for my new gadget -- technical book viewer. I wonder what else it will turn out to be good for?