Well it depends on what you're building surely? Anything with relational data would fit in a RDBMS more than it would Mongo. E-Commerce is one area that isn't

Well it depends on what you're building surely? Anything with relational data would fit in a RDBMS more than it would Mongo. E-Commerce is one area that isn't `ancient` and that would need the reliability of a traditional ACID compliant DB like Postgresql.