Digital preservation involves managing digital materials over time through curation, archiving, and preservation strategies to prevent loss of content and prolong their existence. Issues with digital preservation include lack of permanence in digital media which can change or corrupt over time, dependence on specific computer systems for readability, and multiple evolving formats. Strategies for digital preservation involve improving digital storage, refreshing digital data through copying, migrating to new formats, technical emulation of old systems, and digital archaeology to recover unreadable data. Pioneers of digital preservation include organizations that archive websites, newspapers, films, and other born-digital materials through programs like NDIIPP, National Audio-Visual Conservation Center, and National Digital Newspaper Program.