User @ domain.tld as ID (Once again)

[Martin Atkins]

Granqvist, Hans wrote:
>>Also, unless you can come up with a way to map an email 
>>address onto a URL that doesn't involve "magic" URLs that 
>>...
> 
> 
> How about mailto:user at domain.com? 
> 
[...]
> 
> I think any identifier that is a proper URL (that is, including 
> a scheme) could be valid.  Or the protocol could limit it to the 
> http[s] and mailto schemes, to begin with.
> 

Throughout this discussion where I've been saying "URL" I've really 
meant "HTTP URL".

YADIS won't work on a mailto: URL because you can't retrieve it to 
discover its capabilities. The operation "retrieve" doesn't make any 
sense on mailto:, since it's not really a protocol.

In theory you could use an ftp: URL, since you can retrieve a capability 
document from that, but support for FTP and other protocols is much more 
of a burden to put on consumers, and the document as it currently stands 
depends on some HTTP-specific things such as the Content-type of the 
response.

(and when I say "HTTP URL", I'm also including "HTTPS URL", since HTTPS 
is of course just HTTP over SSL.)