I use twitter for news, follow scientists & technologists, I see many links there before HN.

I think platforms like FB are for showing off and looking for chicks and stalking people.

SN interest me because they are yet to be explored medium. There are many algorithms that enable you to find out nifty things. See https://github.com/clyfe/cywiky/wiki/Social-Media-Analytics and http://www.hilarymason.com/