How does Facebook alert me on Instagram that Facebook friends have joined the service?

[Kevin B]

I don't like to use facebook but i only have it for family contact. I have instagram which i use very often, and i keep getting notifications from FB that new friends have joined the service. I know that FB now owns IG but i don't even have FB connected to IG, nor do i use the same emails. I've checked in the IG settings and i'm not connected to FB, i've checked on FB settings and it's not connected to IG. How is Facebook able to contact me with that information and how do i avoid that?

[Ponies173]

Because more than likely your using the same email address for both websites or name so Facebook is informing you only by the email address they have in their system and on instagram
It could just be your using the same name as your real name like not the username but the one that's under that

[Moses]

Definitely the name you're using on IG must be similar to that of FB,and if that's the case you will get alert constantly on your IG. I do get it everytime as well. Good Luck