Overall look and feel; The ipod is pretty slim and has a good design and maneuverability through the music. And that new click wheel is so sexy, apparently. Not to mention advertising. Ipod is all over the place, I’d be lucky to walk out my door and not see something related to it, in fact, I feel pressured to buy one everyday, good thing I got a free one.
Also, apple has established a solid market for them; the brand name. People know and trust that this device is reliable, working, and it looks damn cool. Everyone has been buying ipods so the people who don’t have one are like: “Hey, wow!” and want to get one. They head over to apple store or apple.com, order one, and get other people to order ipods. All in all, I think two things: excellent market establishment /implementation and Style. Okay, maybe that’s three things technically, but you see where I’m going. And most of the products have seen that ipod is teh win, so they design around the ipods and not something like the iriver. There are some products for it, just… not so many.