O'Reilly Media introduces another innovation in publishing--books by the chapter. You can now purchase a PDF of just the sections of a book you're interested in. (You can also purchase rights to reuse any part of a book in different contexts, another nice touch.)
My Smart Home Hacks is available this way too. Let's say, for example, that you want to automatically forward calls from you home phone to your cell phone, whenever you leave the house. Now you can buy a copy of "Forward Phone Calls" (in Chapter 2) and put it to use right away. Sweet.