the iPod introduction wasn't actually at a convention. Apple sent out invitations to the media about a new product, so in fact, it was an iPod-exclusive presentation. where you can find the video of it....i have no idea, sorry
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it's funny remembering some of the posts immediately criticising the iPod following the introduction of it (expensive, not revolutionary, etc.). apple proved a lot of people wrong in the past 3 years (at least i think it's been 3 years).