<quote_kim_cameron>
How hard is that? It would be the same process copying the file to some other device. It works fine. As easy as getting a word document or powerpoint or mp3 from one place to another. Dongle anyone? How about email?
</quote_kim_cameron>
IMHO comparing Identities (especially the self issued in case of CardSpace) to mp3 and power point presentations is against the user centric aspect of any identity meta system. I say so because for me user centric is more than just making user choose an identity/avatar, it is also about the ease of use, awareness of the usage and some enforcements so that user does not make mistakes unknowingly.
Sure copying files from one machine to another is easy but synchronization of those cards and vulnerability of leaving those cards on different machines create risks. I do not care about leaving the traces of my mp3 and ppt but identity I do care. Yes, you may be smart enough to delete them after the usage but people (the masses, the grandmas) whom we want to use identity systems may not be and worst would be that they may not know that they left their identity behind after usage. Things that seem easier and natural to us are complicated for common users. Identity systems will be new to them and we should make sure that they make less and less mistakes. Copying card files to other machine and not deleting them would happen.