That being said I use to have a lot of engagement on my twitter account and I got to the point that posting would give me anxiety because of the possibility of negative replies despite whatever I said being mundane. Also watching others get "exposed" for certain behaviors gave me anxiety as a somewhat popular person in my social network. I wanted the engagement, but after I got it I found out it wasn't what I was expecting/wanted and stopped.
I guess I didn't really have a secret as much as just learned the hard way.
edit: couple hours per week*
Replace broadcasting with a duplex channel.
In retrospect, my urge to post and share something on social media is just an urge to satiate my ego and be noticed. I think the reality is that most people don't really care about the majority of what someone else has to say, so making something personal and intentional is your best bet (and a great litmus test for whether or not future communication on a given topic will be worthwhile).
Edit: typo.
This way people who like to hear from him are able to. he always invites replies and often times I just write my thoughts on one or two things he wrote.
1. First, sleep on it and let the urge fade away.
2. For the remaining urges,
2.a if the urge actually turns out to be an urge about writing and not so much about communicating, write a blog. Perhaps one that you don't even tell your friends & family about, if it is really about setting things down on 'paper'. Or one you tell them about and they will or won't read.
2.b as others have said, e-mail, if that's more about communication. Communication which will happen or won't; in my experience people rarely answer when there is no explicit question in a message (and even then, hem...), but that depends on people I guess.
Perhaps write the tings you want to share down and send them out as a quarterly update? That would have the effect that you are not imposing too much, and that you have some time to reflect on what you want to share (so you are less likely to share pieces that make you angry or that only have temporary impact).
I am not on a social media with my mum, but when I see something that might interest her I send her the link in an Email.