You may have seen a few of these cryptic little square patterns recently : they've started popping up in all sorts of places. In case you're wondering, they're called QR ("Quick Response") codes and they're definitely worth knowing about.
QR codes are basically two-dimensional barcodes. The code above contains the URL for this blog :
http://spellmaking.blogspot.com. So what? The point is, smartphones, tablets and other devices these days will most likely have a camera in them to allow such codes to be read as well as the software required to interpret them. So by pointing, say, an iPhone at this image printed on a piece of paper somewhere, you'd be able to browse to this web site without having to remember and/or type in the URL. QR codes allow you to easily grab web site addresses from somewhere out there in the physical world and onto a computer. For writers, they're another way of letting readers find your web site, blog or whatever. That's why you see them more and more on the back of books, on promotional bookmarks, on adverts.
QR codes are easy to generate and don't cost anything to make. I used
this online generator to create mine (althought his one says non-commercial use only; there are plenty of others). They don't, incidentally, have to be used just for URLs; they can be used to encode anything.
Why not just spell out the actual URL? That's because computers are bad at interpreting letters and numbers. Human brains and computers are very different things. You're good at pattern-recognition; your poor, mindless computer isn't. That's why you often have to type in strings of characters on blogs etc. They stop someone automatically generating a zillion spam posts. When a computer tries to interpret a URL it can easily make mistakes. But a computer can read a QR code effortlessly.
So, if you're producing some marketing material or publishing a paperback, it's well-worth considering adding in a QR code along with all your human-readable contact information ...