There is a design difference in how the activities look based on the fact if they were submitted as out of a store or as an in-store activity.
An out-of-store activity means that a rep has not visited a place and just submitted an Activity without checking in to that place.
Please take a look at the examples to see how those activities look in the feed.
When exporting, you can also see this status as a separate column called "Checked in".