
This is the text that appears in the subject line of the email that is sent to your visitors' friends. Using the words "site" and "sender" wrapped in square brackets tells the system to automatically replace these values with the site and sender's names. For instance, if your subject line is:
[sender] has sent you a link to [site]
The email sent by a visitor to MyDomain.com called Jack would look like this:
Jack has sent you a link to MyDomain.com