Summary
reports are similar to tabular reports, but also allow users to group rows of data, view subtotals, and create charts. They can be used as the source report for dashboard components. Use thistype for a report to show subtotals based on the value of a particular field or when you want to create a hierarchical list, such as all opportunities for your team, subtotaled by Stage and Owner. Summary reports with no groupings show as tabular reports on the report r

By
adding a contact lookup field on the lead form you can track thecontact that made the referral.

1. You can track how often the content you issued is viewed
2.Youcan control how long the delivery is available to viewers
3.You cancontrol if a viewer can download a file or view online only