Google introduces "read receipts" an optional feature for Google Apps for Business and Google Apps for Government accounts.
"Read receipts allow senders to monitor the status of the messages they send and allow recipients to acknowledge receipt of mail. Let's say John works in sourcing for his company and wants to make sure that his suppliers receive his purchase orders. As he sends each one out, John can request a receipt and later check that the recipients have received the orders. Conversely, if someone sends John a message with a request for receipt, Gmail can send a receipt to the sender when John opens the message. Read receipts work both internally within your organization and externally, so they can help improve communications with customers and partners," explains Carl Haverl, Software Engineer over at Google Enterprise blog.
"Google Apps admins can now log in to the control panel to enable read receipts for their domain. Administrators can choose whether users need to manually approve receipts or whether receipts can be sent automatically. Automatic receipts can only be sent to users within the same domain and to a list of email addresses defined by the administrator," Haverl said.
To activate read receipts, log in to the administrative control panel of your Google Apps for Business or Government account and look for "Email read receipts" on the Settings page for email.
For more information, please see Help Center.
[Source: Google Enterprise blog]