Graph databases are a natural fit for delivering real-time recommendations in online commerce, as they can easily capture and analyze large amounts of buyer and product data to gain insight into customer needs and product trends. This technology is quickly leaving traditional relational databases behind and is now available off-the-shelf, with Neo4j being the most popular graph database. It supports many named, directed relationships between entities, giving a rich semantic context for the data, and queries are super-fast since there is no JOIN penalty. Graph databases are especially suited to formulating recommendations as they can understand the customer's past purchases, quickly query this data, and match the customer to the people who are the closest match to them both in their social network and in buying patterns. With Neo4j, businesses like eBay have seen significant profit and productivity improvements over traditional relational systems.