Similar to Hacker News for me: interesting tech articles and discussions, but with a different feel. I follow a bunch of graphics programmers and machine learning researchers. There's a lively community with a bunch of famous people participating as well as lesser known people who are really good in certain niches.

Particularly in machine learning it seems like thousands of papers are published every week, impossible to sort through. I find that the few I see people talking about on Twitter are the most interesting and worthy of attention.

Here's a list I made a while ago of the machine learning people I follow: https://www.reddit.com/r/MachineLearning/comments/b6dwrd/d_b...