So, what is it exactly you're asking here? I'm confused.
If it's something like FB where you can have a post for friends or friends of friends or public, maybe that will be available in the communities the developers are working on.
BUT, that is only here on Steemit. Steem still has all information readily available for everyone, as a blockchain should.
There is no way you can have a post only visible for certain groups or people,, it's just against how a blockchain works.
This means that even if Steemit has a "block" function in the future, alternative frontends won't need to incorporate that and can show everything.
Or you can go directly into the database and retrieve all the information.
If you have something you do not want to share with everyone, don't post it.
It's that simple.
there is a built in way to encode for keys... anything here can be private by encoding...
I'm not sure that's correct, at least I have not found any info about that.
Yes, keys are encoded, but as far as I know that's the only thing. For posts to have the same functionality I think some changes need to be made in Steem.
I was thinking more like blocking individuals from interactions. Prevent trolling, posting, and display (here if nothing else) to blocked persons.
Mainly as a way to deal with spam and trolls.
The only option you have at the moment is downvoting. If that happens enough they will disappear.
Unfortunately, that's all power based. Really puts the new (weak) at the mercy of the old (strong).
Someone with anough SP going around trolling newbies with flags and harassment is pretty much untouchable unless a stronger fish comes along to save them.