Currently, the majority of electronic publications are static documents, i.e., they are not changed once they are released. Users may be able to change underlying data interactively according to their needs, launch virtual experiments from embedded software or add comments to networked documents, thus creating a dialog with the authors and other readers. However, the original document remains unchanged. Archiving institutions will have to decide whether or not comments and other additions should be preserved together with the publications. A subset of networked electronic publications are dynamic documents which can be modified after publication. Archiving all versions of dynamic publications is difficult. Probably only ``snapshots'' of the available data can be taken at regular intervals. Alternatively, the entire record of changes will have to be logged in order to be able to reproduce all changes carried out after release of the original document.
Electronic publications can be stored on a variety of physical media. If high user demand can be expected, archiving institutions may decide to provide publications online on networked servers in order to reduce access times. Otherwise, offline storage might be more appropriate (and cheaper). Theoretically, electronic publications provided on networks can be accessed from anywhere at any time. Documents remain interconnected, i.e., they can contain active hypertext links to other digital documents and vice versa. In practise, however, global accessibility requires stable and fast telecommunication networks worldwide which are not yet in place.