An email that you send as part of an email blast goes through multiple Statuses. The Email Tracking tab has an entry for each Status that the message goes through.
The possible Statuses for an email are:
You will see an entry in the Email Tracking tab for every single Status that each of your emails goes through. The Email Tracking tab lets you know if the emails sent using PK4Connect was delivered, bounced, opened, etc. You can use this information to build a variety of analyses and reports to help improve your campaigns.
Status records grow quickly in numbers, so they can take up a lot of Salesforce storage. They can be set up to be periodically deleted. And they can be manually deleted, too.