Sync Reports tab is where you can find your Sync Profile's syncing details. Where to find it? Easy! Just follow these very simple steps or watch a quick video (Constant Contact for Salesforce example integration)
Head over to your SyncApps account then on the side tab press "Reports" then you will see the Reports of your Sync Profile(s).
The Summary Charts give you an idea of the number of records say are "updated" from a software, meaning the record changed like a field on the record. Examples of Field Mapping are shown here.
In Constant Contact's case above there were 560k+ records that had an update to their Salesforce or new Constant Contact record this month and transferred that data to Constant Contact or back to Salesforce.
Opt-Out status is not included in this number on the reports as that process is handled by default bidirectionally between all systems you are integrating on the platform.