user@domain URNs, independent from OpenID spec

[Xageroth Sekarius]

Interesting points but ultimately it's still an e-mail address. If I
share it with someone it won't be my OpenID, it won't be my webpage,
it won't be my phone number or my zip code, it will forever be my
e-mail address even... when you make it so that it isn't. Stepping on
top of (arguably) the most shared personal identifier with a
completely different usage and no actual correlation between identity
layers is not a weak point.

Explaining the difference to nerds? Easy as hell. Explaining why that
e-mail link is not broken even tho it took your Mom to a webpage
instead of opening Outlook? Much harder.

It's also confusing from a robot perspective if you think about it.