Ignoring the technical difficulties others have mentioned, the fundamental flaw to me is that other people set the response times. This is akin to Outlook's pr

Ignoring the technical difficulties others have mentioned, the fundamental flaw to me is that other people set the response times. This is akin to Outlook's priority markers. There's nothing wrong with prioritising, but it needs to be you who sets the priority, not everyone else. Your "queue" would always be poisoned with people wanting fast respones (And who ever sends an email and hopes for a slow response??)