approved: Confirmed from personal experience - I looked at a notification I recently received myself from Facebook, and it had a zero-pixel image whose source URL was "https://www.facebook.com/email_open_log_pic.php?mid=..."
This point seems wrong since it seems that there is no useful content.
Previous Title: No changes recorded
Updated Title: No changes recorded
Previous Analysis: No changes recorded
Updated Analysis: No changes recorded
Previous Status: PENDING
Updated Status: APPROVED
Updated Title: tracking pixels used in service-to-user communication
Updated Analysis: AH!
Updated Status: PENDING