A block bounce is a type of bounce that occurs when an ISP rejects an email because of the sender's reputation or content. This indicates that the ISP views the sender as a potential spammer or has received complaints from other recipients.

In Salesforce Marketing Cloud's Journey Builder, ensuring that "Journey Data" is utilized for decision splits is crucial for accurately directing subscribers through the journey based on real-time interactions or behaviors captured at the point of entry. Journey Data references attributes from the Entry Source, allowing for dynamic pathing based on data specific to each subscriber's interaction within the journey itself, thus enabling personalized and relevant experiences based on up-to-date information.
Reference: https://help.salesforce.com/

To monitor whether all records are being added to the target data structure each day in a scenario like that of Northern Trail Outfitters (NTO), the feature "Run Completion" within the File Drop Automation is most relevant. This feature allows the admin to check the status and results of the file drop automation, which includes verifying if the automation successfully completed and how many records were processed and added to the data extension. Using this feature, NTO can monitor daily imports and identify any discrepancies in the number of records processed, which could explain why fewer subscribers than expected are being sent emails.
References:
Salesforce Marketing Cloud Documentation on "Automation Studio" and "File Drop Triggers"

When using a filename pattern for a File Drop Automation trigger, the import File Activity should use %% FILENAME_FROM_TRIGGER%% as the file name. This ensures that the import activity will use the same file name as the trigger, regardless of the date stamp or other variations

To enhance mobile adoption strategies, Northern Trail Outfitters can leverage the following reports:
A). Email Performance by Device: This report provides insights into how subscribers are interacting with emails across different devices, which can help NTO understand device preferences and optimize their mobile content.
B). Time Between Send and Engagement: This report tracks the time it takes for recipients to engage with emails after they are sent, helping to determine the effectiveness of timing and content across different platforms, including mobile devices.
Reference: Salesforce Help - Discover Reporting Tool