What is the difference between unique and total views?

Unique Views

A unique view is recorded the first time a recipient opens or views a campaign. A maximum of one unique view can be recorded per recipient.

Views are not recorded for any recipients who have images disabled or blocked or who read the message on a mobile device that does not display the full HTML content.

Total Views

The number of total views includes the original unique view, plus any additional views - which could be additional views by the original recipient or possibly via a preview pane, or if the recipient forwarded the email to additional recipients who then viewed the campaign. The tracking image used to record activity for campaigns is uniquely tied to the original recipient, so any views by additional people the original recipient forwarded the campaign to will be recorded as addtional views by the original recipient.

Examples

• If a campaign was sent to John Smith and John opens the email once, one unique view is recorded. 
• If John opens the email again, this will be recorded as two total views (one unique view remains as is). Each time John opens the email - either by opening it in a new window, or by displaying the content in a preview pane - the number of total views increases.
• If John forwards the email to several colleagues by hitting "Forward" in his email application, and two of those colleagues also open the email, this will be recorded as four total views.
• However if John clicks a "Forward to Friend" link from within the campaign content, anyone who views the campaign after receiving it from him will be recorded as a referred view. Referred views are not included in the number of total views.