The creation, management and use of digital materials are of increasing importance for a wide range of activities. Much of the knowledge base and intellectual assets of institutions and individuals are now in digital form. The term digital curation is increasingly being used for the actions needed to add value to and maintain these digital assets over time for current and future generations of users. The paper explores this emerging field of digital curation as an area of inter-disciplinary research and practice, and the trends which are influencing its development. It analyses the genesis of the term and how traditional roles relating to digital assets are in transition. Finally it explores some of the drivers for curation ranging from trends such as exponential growth in digital information, to "life-caching", digital preservation, the Grid and new opportunities for publishing, sharing, and re-using data. It concludes that significant effort needs to be put into developing a persistent information infrastructure for digital materials and into developing the digital curation skills of researchers and information professionals. Without this, current investment in digitisation and digital content will only secure short-term rather than lasting benefits.