If you upload any content to facebook, you cease to be the legal owner of that content, so your famil pictures are nolonger yours and facebook can sell that content to corporations for them to use, so one day you could be driving down the road and see yourself on a big billboard in an advert for whatever is being advertised and you won't see a penny in revenue for your image being used.

I am surprised you are not aware of this as its well known how FC derives some of its income, it sells access to data, sells advertising space, sells content, etc. You didn't think Zuccerberg made his billions by advertising alone did you?