Hi,
1. The article properties are documented
here.
`keywords` is extracted from the RSS feed and will vary widely between sources (it may not be present at all)
`entities` is the result of our NLP and machine learning processing.
We only analyze feeds followed by pro+ and enterprise, so it may not be present in all articles.
2. Entities are probably your best bet. Note that we only list entities referenced in the article, so if the article doesn't explicitly mention vaccination in an article about Covid-19, the entity will not be returned. With that said, we currently expand the health-related entities and return categories as well (e.g. "infections", "virus diseases"). Here's an
example.
I hope this answers your questions.
--
David Chatenay
Platform Engineer
Feedly