There are many forms that ask for information and in most cases you have to tick to accept their emails and often emails from 'Third Party' groups which are generally advertising. As part of the sign up process you could choose which options you want and that could include the following;

I am happy to share with everyone except for that weird kid in second grade.

I am happy for Facebook to make billions out of my data - It makes me feel valuable.

I am happy to share with the Russians - especially those nice women who write to me all the time.

I am happy to help the Russians elect Donald Trump.

Who cares - I am so boring nobody would be interested in my shopping preferences.

(Tick any or all that apply to you)

The only other option seems to be to not sign up or never use it again.

Dennis Fitzgerald, 

Melbourne