For more than twenty years cookies have been on top of the tracking digital marketing hierarchy allowing marketers to find users based on their online characteristics and behaviors and deliver advertising to them on the web. This allowed marketers to provide more relevant advertising to individuals, but the golden era of the cookies is now gone, and many people are wondering how to do digital marketing without this useful tool. The end of cookies represents a big challenge to all digital marketers, but there is a number of testing strategies that can be used, and in this article, you will find some of the main ones.