¿Free Shipping on Half.com Purchase with FreeShipping.com?

I purchased an item at Half.com and the confirmation email contained a link to a web page called FreeShipping.com, which offers reimbursement of shipping fees.
Have any of you signed up for this offer?

 

Avoid it, if it is what I think it is. After a purchase from a reputable seller or site, many of these companies offer free discounts and cash back if you hand over your credit card. Then you are often enrolled in a club or membership with little benefit, except to drain your wallet.