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Re: Ian Fleming
Once is happenstance. Twice is coincidence. Three times is enemy action. -Ian Fleming, Goldfinger
Chatting on WhatsApp with a friend. They type the word Bebras. Next day they get an advert on Instagram for Bebras.
This is such a specific keyword that there is no way whatsoever for it to be happenstance.
We are outside of the age range of the challenge, neither of us teach at schools, and this is such a niche topic that there cannot be a random advert for it.
We are finally convinced that Meta uses the contents of WhatsApp messages to serve advertisements on Facebook and Instagram.