So com.gmail/cydeweys maybe?
Or it could be just an object in a global namespace (accesses through a protocol specific facade). So com.gmail.cydeweys
com.gmail.cydeweys doesn't really work because you need some way to distinguish that as an email address and not just a subdomain on com.gmail. So it really does need a different delimiter, like how you need a different delimiter in URLs when it switches from the domain to the path (and then also to the querystring and fragment).
https://en.wikipedia.org/wiki/At_sign
It was used as 'at' in computing in Algol 68 where it was a shorthand for a keyword 'at'. It has a different application as 'at' in Dyalog APL.
https://com.google. for the main page
https://com.google.mail for gmail
https://com.google.mail/localpart for one's own gmail account
mail://com.gmail/localpart to send mail to what is currently localpart@gmail.com
Alternately, we could continue to use '@' and put the localpart first. The URL method of specifying a username or username and password does this for HTTP/HTTPS.
http://username:password@com.site/login
And currently we use mailto:localpart@example.com but we could use mailsend:localpart@com.example instead.
The other nice thing about this system, is that you can drop the domain when the communication is internal.
And if you really wanted to, you could force the communication protocol xmpp//com.twitter@dan vs smtp//com.twitter@dan
But I could _kinda_ of make an argument for it. When I open my browser, I want to go to "the homepage of the company running New Your Times, so homepage@com.newyorktimes - or perhaps the menu from French Laundry - menu@com.frenchlaundry