This is useful! I was hoping for something based on topic modelling [0] though. Keywords are useful, but often are out of context. e.g. I looked for "writing", and many of the matches have nothing to do with writing as topic, but simply mention it in the headline.
Conversely, there are often topics in the post that are not in the headline.
Conversely, there are often topics in the post that are not in the headline.
[0] https://en.wikipedia.org/wiki/Topic_model