Having not had the capability for a while for whatever reason, I had to try it out when I finally could.
The capability is iSight, a user-facing camera which is these days built into every laptop Apple makes. (And that's every one, including that poufy, flouncy little Macbook Air.) It can be used for other things, like the folks at Delicious Monster realized when they built their application Delicious Library.
The idea behind Delicious Library was to build a fairly intuitive iTunes-like interface for the cataloging of physical objects, like CDs, DVDs, books, and games. They even make it easy to get the information into your computer by letting you scan a barcode if you have a convenient camera handy (cough). Then they go online and fetch all the particulars of the thing you scanned.
I wanted to try it. And the demo version allows you to scan up to 25 items. So hey, I could try it.
The first books I held up to the camera (using the camera view window as a guide), it picked right up. As an extra delightful feature, it read the name with the built-in text-to-speech engine.
The fifth, it searched for a few moments and then balked. It couldn't find a book corresponding to the UPC of the book I held up to it. A wonderful thing got cut ever-so-slightly low in my sight.
And frankly, I can't blame it for failing. The first four books I showed it were cookbooks, by noted authors and commercially available. The fifth was an incredibly obscure roleplaying game book that I had picked up two nights before, and just happened to have by my feet.
That incredible convenience of using a barcode scanner to read your library into your computer? Not so much so when you have two hundred or more books that it might not be able to read, neatly stacked on shelves in another room.