mystified by mailto address

[Jeremy]

>Well, i just tried with the '+' in there;
>see how it goes.
>I've never seen a + in a username before.

ObRant:
(with thanks to Randall Schwarz)

There is no reason why you can't have a + in an email message. 

According to RFC 2822, an email address may be any ' Non white space controls
and The rest of the US-ASCII characters not including "\" or the quote character
'

So people are allowed to have addresses like ^_^@squint.com.  Unfortunately
many mail server writers have, for reasons that are never explained, limited
the character set.  For instance, I was disappointed to see that Courier Mail
throws an 'invalid address' when it sees a ^_^.

Most people seem to think that email has to follow the same rules as the DNS
system, when email predated the DNS system by a number of years.