I followed a link someone had posted on FB regarding FB (and other sites') tracking behaviour, and it took me to this site where apparently you can 'opt out' of having your browsing habits spied upon.
YourOnlineChoices.eu - Your ad choices
This is the EU page, there are different ones for US etc.
YourOnlineChoices.eu - Your ad choices
This is the EU page, there are different ones for US etc.