A look at the message trace feature in the Office 365 Security and Compliance Center for tracking email message delivery in Exchange Online.
Tracking Read Status of Email Messages in Exchange Server
How to use delivery reports in Exchange Server to check the read status of email messages.
How to Tell Which Transport Rule Was Applied to an Email Message
Is there a way that you can tell which transport rule has been applied to an email message?
Troubleshooting Email Delivery with Message Tracking
How to use message tracking to troubleshoot email delivery issues in a Microsoft Exchange Server environment.
Message Tracking and Proxy Addresses
How to use message tracking log searches in Exchange Server to identity usage of secondary email addresses.
PowerShell Script to Create Report of Exchange Server Message Tracking Log Configuration
This PowerShell script will generate a CSV report of the message tracking configuration of your Exchange 2013 servers.
Exchange Server FAQ: Does Message Tracking Include Bcc Recipients?
Does Exchange Server message tracking allow administrators to track emails sent to Bcc recipients?
The Case of the 739,254 NDR Message Loop
The case of an Exchange Server environment experiencing very high message traffic due to an infinite loop of non-delivery reports.
Speed Up Multi-Server Message Tracking Log Searches with PowerShell Remoting
How to use PowerShell remoting to speed up message tracking log searches across multiple Exchange Hub Transport servers.
Searching Message Tracking Logs by Email Subject
How to search Exchange Server message tracking logs for keywords and phrases in email subject lines using PowerShell.