While the RFC mandates the ability to send and receive email from user+detail@example.org it doesn't require that it go to user@example.org. It's an extension t

While the RFC mandates the ability to send and receive email from user+detail@example.org it doesn't require that it go to user@example.org. It's an extension to the email standard, and you could have labels in another form if you wanted to, e.g. inbox0-user@example.org (http://tools.ietf.org/html/rfc5233 http://tools.ietf.org/html/rfc5233)