Graph databases are designed to scale out across a distributed cluster, with TitanDB utilizing Cassandra's distributed storage engine to achieve this advantage. In contrast, Neo4j scales up and relies on a master/slave architecture, requiring more powerful machines for scaling. The choice of approach depends on the tradeoffs between performance, reliability, and scalability. Some databases, like OrientDB, offer hybrid document-graph engines that blend SQL with graph manipulation capabilities. These differences highlight the varying design philosophies and technical approaches of graph databases in a distributed platform.