The unfortunate reality is that people are lazy and nearly no one would curate to this degree. 

Many (now dead) social platforms have tried and it always turns out the same (remember circles in Google’s Facebook killer?)

I actually think the use of lists and having clients that allow filtering/switching feed content based on lists is a much more useful/manageable way for most people to accomplish this. 

It also allows you to take advantage of other people’s curation work so everyone isn’t forced to do all the citation themselves (which, again, they just won’t do).