What every software engineer should know about search

Ask a software engineer: "How would you add search functionality to your product?" or "How do I build a search engine?" You'll probably immediately hear back something like: "Oh, we'd just launch an ElasticSearch cluster. Search is easy these days." Numerous current products still have suboptimal search experiences. Any true search expert will tell you that few engineers have a very deep understanding of how search engines work, knowledge that's often needed to improve search quality.