The Library of Congress has produced a video that provides a nice beginner’s guide to some of the issues surrounding the long-term preservation of digital assets.
See the video here.
From the video’s description:
Traditional information sources such as books, photos and sculptures can easily survive for years, decades or even centuries but digital items are fragile and require special care to keep them useable. Rapid technological changes also affect digital preservation. As new technologies appear, older ones become obsolete, making it difficult to access older content
This video explores the complex nature of the problem, how digital content – unlike content on traditional media — depends on technology to make it available and requires active management to ensure its ongoing accessibility.