I think http://www.ribbonfarm.com/ and http://slatestarcodex.com/ are sites that are fairly well know among this crowd, but have consistently thought provoking content. If you enjoy meta-thinking or reading about complex societal dynamics, you're in for a treat.
I know it's not a secret site, but my reading consists of paid subscriptions:
- NY Times
- Wall Street Journal
- Hacker News for tech related news
A lot of people are against paying for news - they feel it is free elsewhere or they can google the title of the article.
For me I noticed that reading the NYTimes and Wall Street Journal provides me curated news with the in-depth high quality coverage I like and leaves me feeling informed.
I avoid reddit as I find myself spending a lot of time on it, similar to facebook.
Newsletters like http://allthesmallthings.co/ is great has also given me some info on design which I find interesting.
I've discovered it a couple of month ago, and I'm so happy I did, now I visit it almost every morning. It has so many brilliant digital artists and mindblowing artworks.
Even if you're not that into "art", it's so fun to just watch people doing something with incredible level of expertise.
Just so fucking good. I can't recommend it enough.
https://longform.org/ I don't visit as frequently as I used to, but it's an excellent source of curated long form articles; brilliant Sunday morning reading.