Clicking on the "Stats" links next to a completed campaign will bring up a pie chart that lays out how your message was received:
Those stats can be represented as any of the following:
Sending: Messages that are on their way to the final recipient.
Sent: The Listbaby server successfully sent the message. There has not been any confirmations received about the message.
Delivered: Messages that have been delivered to the recipient's mailbox. They may have been opened if the recipient has image loading disabled (Not all clients support this)
Opened: Messages that have been read by the recipient in a full (images-enabled) client (Not all clients support this.)
Bounced: Messages that will not be delivered; most likely due to an improper address, full mailbox, or other error with the receiving mailbox.
NOTE: If a contact bounces 5 times in a row, they are removed from the list.
Other: Messages that most likely did not send due to other circumstances.