Is "times mentioned on a job advert" really an accurate measure of whether or not something is still used? Surely it lags years behind trends - if a technology is abandoned quickly there'll still be jobs maintaining the old code that need that skill. That doesn't mean the technology is still 'useful'. For example, there are still plenty of COBOL job ads around.

I'm not suggesting that's the case for NoSQL, just questioning the way you're measuring it.