Differences between Twitter and Facebook
There are fundamental differences in the way one connects with people, on FaceBook and Twitter.
On Facebook, one connects via 'Friend' requests. One party sends a “friend request” to the other. If the recipient accepts, then they have a connection. On Facebook, generally, one only asks to connect or accept requests from people one genuinely knows and not accept requests from those one doesn’t (with a couple of minor exceptions). In other words connections are with people with whom one already has a relationship.
On Twitter 99%+, of the people we follow or who follow us, start out as strangers (not least, because usually none of one's friends, on FB, have Twitter accounts and those, who do, rarely tweet or access their accounts). This affects both what to talk about, how to say it, how to stay safe and how to avoid potential bullying, etc.
A key difference is that one may be more tolerant of friends, on Facebook. Most people are not interested in seeing pictures of someone's lunch on FB. Some of one's friends have very right-wing views and post accordingly but there is a bond and they may be tolerated, up to a point. On Twitter there is less “loyalty”. You can unfollow/block at the drop of a hat. Mostly, they are not your friends.
In Facebook there is a degree of trust already. On Twitter you have to build it. The rules are different.