This paper outlines how many online retailers today have benefited from using Neo4j over common relational database management systems to maintain their connected data resources and build intelligent applications for their customers. These applications are important in terms of being able to provide the customers with cutting-edge conveniences and maintain a solid competitive advantage in an industry that is in constant flux.
Going further beyond, I have also benchmarked the query performance of a popular RDBMS, MySQL against that of Neo4j in the context of a product recommendation engine.