It's strange, because a lot of people have asked me "How do you know him/her?" when I have someone on FB. But no one asks me how I know someone in real life off Twitter & any social media sites. Why is this?
Twitter and Instagram are more "public" compared to facebook, which most people use just for friends and family
Twitter and Instagram are referred to as followers, not facebook
But you can still add randoms on there if you want, maybe they're just curious
Facebook Designed it like that Because a Bunch of people have met Strangers Online from Myspace and a bunch of Other Sites and a lot of Bad things have Happen
Facebook wants Everyone to be Safe while using there Site
10k Organic instagram followers for $39
they are trying to prevent spammers from ruining your experience