actually returning multiple results doesn't work very well for either email addresses or domains. it might look like it works for email addresses - and if the first time you send to an email address, you get back a "sorry that was ambiguous" response and a list of possible alternatives, you might think this was acceptable. on the other hand, if you're used to sending mail to a particular address or if mail is sent to that address via an automatic process, and suddenly the address becomes ambiguous, this does not make a good interface. similarly, multiple responses for a domain lookup can work fairly well when there's a human in the feedback loop who can respond in real time and who knows enough about the nature of his request to be able to supply enough information to narrow down the choices to one. but it doesn't solve the problem in general. Keith