I've really been enjoying Tildes: https://tildes.net/

It's somewhat similar to Reddit (and was started by a former Reddit admin), but values quality content and discussion over "fluff" content. The users on there are wonderful, and I've had some very good discussions about both tech and non-tech topics. This blog post has some good info on it's philosophy and what makes it different: https://blog.tildes.net/announcing-tildes