At the most basic level, FreeMarker code is a great way to dynamically insert values from Contact/Account/User records into Click email templates. However, the scope for ways to use FreeMarker code is very large, and it can be used for a number of purposes beyond just displaying dynamic content.
Dynamic Content in Links
FreeMarker can be used to pull a value from your environment into a URL as a link parameter or to pull in an entire URL.
Subject Line, From Name, From Email, & Reply To
You can use a FreeMarker interpolation in an Email Send’s Subject Line, From Name, From Email, and Reply To fields by placing the FreeMarker in the appropriate field on the Email Send record.
Time Stamps
You can also use FreeMarker to place time stamps into your emails:
Date only, no time: ${.now?date}
Time only, no date: ${.now?time}
Date and Time: ${.now?datetime}
Note: These are some of the only interpolations that render in Test Emails. They do not reference data on a specific record and thus do not need to be sent to a specific recipient in order to render. Data from records that have a Connection with the Email Send records will also render in Test Emails.