None of this really applies to what is being talked about here. They use the word "stylus", but really they're talking about a 'pen'.
What's the difference? Well, I consider a stylus to be a pointing device - something you use to bring up menus and move around the page, etc. A pen is really more of an accessory for drawing-type tasks (although that's not to say you can't use it to navigate menus and such, just that it isn't its primary purpose).
Styluses are a bad idea - it's much more convenient and intuitive to use your fingers to navigate a device. Pens, however, are very good ideas - they allow us to keep on directly manipulating things on the screen (which is what makes iPhones and iPads so great and so different from PCs), but they allow us to do it more precisely and comfortably (palm rejection).
I would love a pen for iOS. The Samsung pen is basically the only thing I'm jealous of from the Android world. I want that pen, but with Apple's software and system integration.
