For example, Facebook recommends me a friend:
- We really know each other
- We do not have mutual friend on Facebook
- We both have whatsapp and have each other's phone number, but never chat on whatsapp before. Or we are in the same whatsapp group only. Does FB use whatsapp contacts as reference?
- We are not friend on any social media apps, twitter, IG, etc.
- We are from the same university, but graduate year differ in several years. And there are so many students...
- I use Android phone, and I never sync my contacts online.
It happens several times to recommend a correct friend.
I feel curious, in this case, what's the data source used by FB's algorithm to recommend a likely friend?