The question of managing unstructured data is very broad and impossible to answer with a definitive correct answer. NoSQL is different than relational databases but the data have some kind of structure. This structure is different than traditional relational databases but it is not correct to call them unstructured.
NoSQL is a whole new way of thinking about a database. NoSQL is not a relational database. The reality is that a relational database model may not be the best solution for all situations. The easiest way to think of NoSQL, is that of a database which does not adhering to the traditional relational database management system (RDMS) structure.