I use Facebook and Instagram for different reasons/modes. One is for the people in my life, family, friends, colleagues, etc. I also am fairly active on a Makeup/Beauty Facebook group, and have become virtual friends with some of the girls from there. As to Instagram, I don't care who "follows" me because a follow has zero obligation for followback. So if people want to see my pics, go for it.
Another use is one that has been growing much more recently. I use these platforms as a sort of all-inclusive journal. I share my revelations and growths as they come to me, because I know there are a lot of people who go through very similar issues, whether they are trans or otherwise. I make these posts on Facebook public, and the rest of my personal stuff is for friends only. I have to be pretty vigilant about changing the privacy designation for each individual post. As a result, I have gotten requests from people I have no knowledge of, and I just delete them if there isn't a connection.
I suppose I'm seeing myself as a burgeoning public speaker. This isn't at all in an arrogant way, but it's just been developing. So I make sure to monitor what I want seen by all vs. people I know specifically. My Instagram is much wider, since I use multiple tags in each post, so different people will see a post for different reasons. But I like it that way. I realize I am not in the norm when it comes to that though