Ask HN: How to find similar content to an article?

I found myself curious to read more about the `quantum effect` from the HN discussion: https://news.ycombinator.com/item?id=31874296. But I couldn't find other discussions or content linked in the comments. What are some other "similar search" techniques to find related Internet content to a link (or a topic)? Besides: - Searching the topic on HN Algolia - Searching the topic on Twitter - Googling the article name (or Youtube Search) - Google's "About the topic"