With GatedContent.com it is possible to set default values for fields using the Submission URL Query String (QS).

In this example, we will set a default value for a product field based on a QS parameter

First decide what the Query String parameter would be called (e.g. default_product).

Then create a hidden field and set prepopulation so it receives the value from the QS

In this example we will call the hidden field DefaultProduct and it prepopulated from the QS default_product.

Then go to the Product field and add a new rule that states:
On form load, IF this field (Product) is blank AND default_product is NOT blank, then set the value of this field to the field DefaultProduct.

Got questions about using query stings to set default values? Email us at support@gatedcontent.com or click +New Support Ticket above.