The public arenas of streets, bars, waiting rooms, buses and shops having become saturated with advertising, we retreat into audiobubble that deny commercial access via the ears. [Thus too the commercial success of TV shows on DVD - guaranteed commercial free]. Has the 'public sphere always been commercial: One thinks of Shakespeare's Venice, with the merchants meeting to chat about their argosies, and of the place of Lloyd's List in the history of print news.
iPod adds little to the functionality of an FM Walkman except that hint of democratisation: the random shuffle. The big difference is that the iPod is cit off from live radio. The iPod should then be considered not only spatially but temporally: not only a private bubble in the big city, but a removal from the eternal now of advertising. Th aural universe has much to teach Virilio.