True in most cases, but it can be a pretty serious violation of privacy. For example, let's say you post pictures of your family with your children on Facebook

True in most cases, but it can be a pretty serious violation of privacy. For example, let's say you post pictures of your family with your children on Facebook, intending to share to friends, and then someone screenshots that and re-posts publicly. I've never tried a public-by-default social network like Twitter or Instagram. I'd be quite annoyed if one of my Facebook friends took one of my posts and published it to the whole internet. I realize it's something that can happen, but it would feel like a violation of trust. I also think that being able to maintain semi-private spaces on the internet makes it a safer place.