While listening to a presentation on UA given to staff, an issue related to internationalized email addresses came back to my mind. I haven't been tracking UA for a few months now, focusing on other projects. I learned of this list and flipped quickly through the archives. So may be my concern isn't quite on-topic. I mean, this is not about getting software to properly handle the spectrum of Unicode characters. Taking a step back, ICANN is about identifiers, and we are striving towards a globally available system that features uniqueness in the mapping of identifiers to "reality." (One of the core concerns about IDNA 2008 is that the mapping from what's-on-a-business-card to whats-in-the-DNS is two-way and repeatable.) Specifically this has been about domain names but by extension through Universal Acceptance, email addresses. Along those lines I have been thinking about they increasing use of email addresses as identifiers for just about all on-line sites. Stores, utilities, and more seriously, medical professionals have made me think of this, as well as the option to either 1) get a free identifier 2) get one tied to your ISP/utility or 3) create your own. I've come to be a bit afraid about stability of this system. On one hand, the identifier I use is used in many places and in many ways, hence changing it is a pain. On the other hand, who guarantees that the identifier will last "long enough" and not change hands if I (or an executor) don't maintain it. The standard for the mailbox name (as in mailbox@domainname) is that the treatment of the mailbox name is up to the domain name. "Dots" are immaterial to mail operators (which has proven to be a surprise), the "+" might be treated specially, etc. I squirm when I think that there's a desire to think of email names as global and unique. So, in a way, it seems like the wrong foundation for an ICANN effort. (Languages have had to adopt '@' already. Not sure about '+' and other syntactic sugar in mailbox names. Yet I understand the "killer" app necessity of IDN email for the new TLDs. I totally get that, and I bet so do the members of the list, so I won't belabor the point. The question though is - how to you build a castle on sand? It's not clear to me that ICANN could drive a standard handling of mailbox names, I think that would be quixotic. Then again maybe tackling mailbox names isn't necessary, maybe all we really need to do is get clients to work with an expanded definition of what a mailbox name is. (Lurking in me is the thought of "variants" and how they might cause trouble in mailbox names if there's no canonical form as defined in IDNA 2008 for domain names.) Ed Lewis Senior Technologist, Office of CTO