@dusansimic
You don't think that there are some links between Facebook services (Facebook, Instagram and now Whatsapp) which make better analytics of user overall? I think if you visit t-shirt page on Facebook that t-shirt shop ads will appear on Instagram and vice versa. I don't think Facebook accurates ads only on its website, data is shared between Facebook services and Whatsapp will help now more with it. Anyway I hope that ads will reach high level of creepines for people to switch.