Preview Button can be found in the Manage Menu and Analytics Menu. The preview button allows past Weekly Emails to be viewed and displays all comments from a single user.
Viewing All User Comments
In the Manage Menu under Moderate>Comments the Preview button allows all comments by that user to be viewed. Clicking on the Preview button will redirect to a screen with all of the comments by that user.
Viewing Previous Weekly Emails
The preview button in the Analytics Menu under Receive Date>Weekly Update Emails allows for the viewing of stats in previous weekly emails. Clicking on the Preview button will redirect to a screen showing the previous Weekly Email Stats