In a recent post, AKMA called me "an honorary postmodernist." There are some aspects about postmodernism that make me cringe, but to the extent AKMA meant "a thoughtful study of the limits of scientific inquiry, the origins and perpetuation of unreasonable prejudices, and the ambiguities of language," I'm flattered. I do think that AKMA is doing a great service by serving as the conscience, so to speak, of digital identity and the limits of the technology in solving societal problems.
In the post linked above, for example, AKMA alludes to identity being the sum total of all our experiences. I think that's a good way to think about it. That meshes nicely with my thinking on digital identity as well. My digital identity is a collection of bits that represent things I've done or collected online. The digital identity is a woefully inadequate representation of me, the person, because I have many more experiences and interactions offline than I do online.
The other issue with digital identities is that they're so much easier to fashion than real identities. This is good and bad. Its good because you are free to fashion an identity for yourself online that is different than your real identity---maybe one more closely aligned with your inner self than the public exterior you've presented in the offline world. its more problematic when we want to start using digital identities to control our bank accounts because now we need a link between our digital self and our meat self. Of course, Amazon doesn't care how many identities I have or anything about them as long as they all have a credit card with a positive balance.