Politics is a complex topic. If you want to learn more, social media is not the way to do it. Well reasoned books and essays are. If you want to convince others of your positions, social media is not the way to do it. Personal relationships in real life are.

What's left?

Again, you seem to insist on an ulterior motive, completely discounting the value or pleasure of conversation. In contrast, reading is a solitary activity. Have you heard of book clubs? People read books, and then they get together to discuss the books.

Hacker News itself is all about reading articles, and then discussing the articles with others. "If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."