BD is seemingly in an aggressive mood at the moment. o.o
Well, I have an MP3 and its shit, and I like iPods a lot more, but that may be because I have a crappy MP3 player too...
They are the same thing, however, just iPod took on a sleek modern look, good layout and design, tons of marketing, and sorta started the MP3 wave. MP3 is considered a knock off of the original iPod, especially ones the mimic the look, like Zune. They are less popular, because the desire to appear to be wealthy and have more and/or at least equal to the rest of their peers, teens in society today look for the main brand, or the most popular of items.
o.o Is how things work. Its pretty dumb actually, to have to have the best cell phone, the best clothes, the best music player, the best laptop, the best w/e else. It's too materialistic in my opinion.