I have a very narrow circle of people over on Facebook I share with. None of my family is close by, except my mom, and even she is more online than in person because of how much she works. My dad lives in the other part of Europe, my children's godmothers live in other countries so I post to them and a few other friends&families. I don't have WhatsApp nor Viber and I'm not on other social platforms. It does bug me sometimes but then again the circle of folks I share stuff with is the circle I trust.
I am sceptical to post on Steemit tho because you can not deactivate or erase your account here and it's kind of like a permanent tattoo but I think you are absolutely right not to share.