For White Label promotions, we've added the option of transferring parameters from the incoming URL to data of the participating user. This way, the promotion administrator has access to a feature that allows adding identifying fields to the participants from the reference URL they used to access the promotion. 

Example: A brand sends a newsletter to their subscribers with the link to a survey. All users that respond to the survey will enter a prize draw. In this case, the brand will add a parameter to the survey link that identifies each user. The user will receive the newsletter and click on the link. When the users have responded to the survey, they don't need to identify by registering in the entry form, because Easypromos will read the identifying parameters in the URL and add this information to the participating user. 

Discover the details of this feature and learn how to create a user field through a URL parameter in this tutorial.