To my knowledge there isn't much lit on the subject, but I am glad somebody will be working on it as I have done some preliminary work and found copious amount of privacy-compromising 'trackers' on the websites of nonprofit and advocacy groups. In one study I found that 92% of health-related ".org" sites had trackers: https://timlibert.me/pdf/Libert-2015-Health_Privacy_on_Web.pdf - tim