against using user@host identifiers

[Evan Martin]

I'm surprised nobody's spelled this out before:
user at host, while cute, are already well-understood as email addresses.
 As soon as [random user x] sees a form that says "enter your id \n
example: foo at bar.com", they're gonna enter smileygirl at aol.com and get
a bad experience when that fails.

OpenID asserts ownership of URLs, so identifiers should be URLs.

If you want to make a shortcut for URLs, use a differenct character
(like that proposal with a tilde).  But I don't think we can agree on
what URL foo~bar.com is a shortcut for:
 - bar.com/foo
 - bar.com/GetOpenIDProfile.aspx?user=foo  ;)
 - etc.