With the new regulations data collection and partners who process any of your personal data need to be listed clearly in your Terms or Privacy Statement.
Clear listing of use and auditable processes
All collection of data is Opt-Out by default, so you need to be clear and get consent. When asking a person to Opt-in you can group similar intent partners like for advertisers, but the choices should be explained in a clear manner and granular to make choices for each use. This makes data collected for email marketing different from the choice to be tacked by advertising cookies or even shared with another department.
So like this very clear toothpaste label and ingredients on all packaging knowing what is on the inside is important, and should be clear and transparent to the person visiting and opting in. It also needs to be a living process to be documented and can at the request of the ICO be audited.
Photo: Reddit: annon