If you capture the reader's email address in document, expected visitor lists can be used to keep track of who has or hasn't viewed it.

Multiple lists can be created containing a list of 'expected visitor' email addresses. Any lists that you create are automatically applied to your documents and a breakdown of data can be found in the reporting suite of PageTiger.

Example
You may wish to create a list containing the email addresses in your department so you can monitor who has visited a monthly bulletin or newsletter.