Email merge fields insert unique user data -- you can learn more about them here.
You can insert a date into a subject line or campaign using the [DATE] merge field.
Note: You can't use the [DATE] merge field as part of a link.
Here's how to use the [DATE] merge field:
Type this code:
[DATE|0|format]where you would like to insert the date in the subject line or campaign body.There are two parameters: A Digit and a Format.
The Digit: '0' represents the current date. The date can be adjusted by adding or subtracting seconds.
The format: This determines how the date is displayed. The date is formatted according to PHP convention. PHP provides a list of all formats online.
Note: Dates using long-form (Monday, June 10) are only available in English.
Here's an example:
If the current date is June 10th, 2013:
[DATE|0|Y-m-d] will show the current date, displayed numerically: 2013-06-10
[DATE|86400|m.d.y] will show 06.11.13 (as 86 400 seconds is equal to 24 hours).
[DATE|-259200|F j, Y] will show June 07, 2013 (as 259 200 seconds is equal to 3 days).