The document discusses sustainability of cultural heritage linked open data products. It defines sustainability as when running costs are less than value plus shutdown costs. Running costs include technology, content, and staffing. Value includes income, benefits to mission, and intangible benefits. Building sustainability requires maximizing usage, usability, trust, and loyalty among users. Usability, trust, and loyalty develop through community engagement and ensuring the data meets user needs. Sustainability ultimately depends on having championing people to build, support, and use the product.