I am not saying those are bad, but with more established DBs like MySQL and PostgreSQL, you never really saw the same kind of marketing efforts towards developers, startups, etc. It is kind of a newer concept.
That's funny because MySQL used to do exactly the same kind of marketing fifteen years ago: comparing itself to Oracle, "it's a thousand times faster" when it obviously didn't do one thousandth of what a RDBMS does.
History repeats... and has a strange humour sense.
Actually I think that MySQL is essentially the fore-runner of NoSQL. People who have cut their teeth using MySQL as a single-app persistence store or were trying to code to lowest common denominator in order to be portable now see benefits in ditching the idea of a shared database altogether because, well, they never used a shared database.