I don't think that's what OP meant. You can have comments like first.last(notify IM)@example.com see http://blog.dominicsayers.com/2009/02/27/comments-in-email-

I don't think that's what OP meant. You can have comments like first.last(notify IM)@example.com see http://blog.dominicsayers.com/2009/02/27/comments-in-email-addresses/ http://blog.dominicsayers.com/2009/02/27/comments-in-email-a... I just don't understand why they made the spec so complex. Seriously, indefinably nestable comments?