No, that's not a practical solution for the following reasons:

-- The recipients may not have Outlook.

-- Even if they do have Outlook, sending them a specific list of categories would require a custom form.

-- Sending a custom form item to someone would require a lot of attention to detail on your part to make sure that nothing prevents the message from getting there in rich-text format and detail on their part to forward back the updated item.

-- The category list is *your* category list. How would the other person know where they fit into your classification scheme?

-- The recipient may press Delete and not bother to respond, having no vested interest in spending their time to update your records.

-- You'd still have to devise some automatic updating routine if you don't want to completely replace the old records.