On a more practical note, the Opera web browser is about to be released for the DS; Opera will be a cartridge which allows users to browse the web via Wi-Fi from their DS. I wonder how long until Skype or someone release a VOIP cartridge, turning the DS into an internet telephony handset.
Meanwhile, some hobbyist hackers have written a personal organiser package for the DS. It's a download, and needs some hacking to get it to work. And someone else is manufacturing and selling cartridges for running homebrew software on a DS. The PassMe cartridges plug into the cartridge port and take a legitimate game cartridge, which they use for authenticating the code downloaded onto them as legitimate; they are used for running homebrew titles, and absolutely not, it must be stressed, p1r4t3d games. It's not quite clear how one downloads the software image onto the cartridge, though; I imagine it may use proprietary software, possibly running only on Windows.
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