But all that could change. In 2012, an organization called the Internet Engineering Task Force IETF created a new email standard that supports addresses with non-Latin and accented Latin characters e.g. ?????.????. In order for this standard to become a reality, every email provider and every website that asks you for your email address must adopt it. That’s obviously a tough hill to climb. The technology is there, but someone has to take the first step.
via Official Gmail Blog: A first step toward more global email.
The TL;DR is: Google is enabling non-latin chars in email addresses (cf RFC6530). Whether this will encourage widespread acceptance of this is going to be interesting to see; like IPv4, everyone’s gotten used to The Way We Do It Now. And like IPv6, I doubt there’s going to be much switchover unless it’s forced.
One obvious benefit would be to employ char-sets in the email header as part of heuristic anti-spam measures in a more nuanced way (as opposed to “anything non-LATIN-1 gets more weight when spam/ham score is being calculated”) — you’d be able to say “well, we have customers in Russia, so Cyrillic is OK, but we have no market in Asia so Asian languages have a higher spam score”.