I think such a scheme is customer-unfriendly, especially for a small company where there isn't a compelling organizational need to have separate email addresses. For example, if an existing customer wants to both place a new order and get customer support, should they be expected to send two emails, one to sales and another to support? Also, I've noticed that once a customer gets a company's email address in their address book, that's the only email address they ever use. I've seen this first hand with customers emailing the support address to place new orders.