I Agree with OP. From an authentication point of view(Crypto and twiiter like 'verification'),some system or authority needs to verify your identity. I think a

I Agree with OP. From an authentication point of view(Crypto and twiiter like 'verification'),some system or authority needs to verify your identity. I think a Fully Qualified User Identity (much like fqdn) where your username is only part of your FQUI would solve a lot of issues. For example: Alice.blue.hn.de Alice.orange.hn.twitter.us The two FQUI represent different people. Alice is in the 'blue' group,verified by hn which used the 'de' identity authority. Alice is in the 'orange' group,verified by hn using twitter. Twitter used identity authority 'us'. <[hierarchial user name]>.<user group>.<[hierarchial identity verifier domains]>.<identity authority> This isn't a new idea at all,there just does not seem to be a one size fits all consensus on what system to use. Maybe everyone is wary because the DNS hierarchial system isn't doing too well. Unlike domain names,a person is unique,you can't register arbitrary identities under the same authority(at least not without committing fraud)