Relational database technology is a 30-year old technology. It's very good. It's so good, we have tended it use it as a one-size-fits-all-solution. And that is a problem. As more information goes digital, we try to shoe horn into relational databases all sorts of structured information that does not necessarily conform to the nice neat transactions and fixed, long-term data structures of relational databases. Also, RDMS were not designed to deal with Internet-scale data.
What follows are what many might consider pretty heretical thoughts for working with data. But like other heresies, many individuals will agree with these if you ask privately one-on-one.