Links to related resources - including biological databases, unpublished data or other supplementary material too bulky to publish in print, interactive models, movies, and animations to convey ideas that are inherently difficult to express on the 2D printed page. Email links to allow feedback from readers to authors and editors, speeding up international scientific communication. It is no longer necessary to wait for a full issue to be compiled. Economy of scale - purchasing and obtaining printed copy only for specific articles of interest. Although in the long term electronic publication may be cheaper and more efficient, in the short term, as publishers scramble to get online, it is costing money to convert data generated using DTP packages designed around paper publication.
Most users still prefer to browse an original article on paper rather than viewing onscreen.
In the long term, display technology will have to improve. Speed, both of the network connection and of the local computer is often still a huge issue, especially in academic environments where internet links are heavily overused. But emerging technologies such as ATM will make a big difference over the next couple of years. Online communitites BioMedNet is working hard to develop the online potential of journals offered in its library. Well, first, it has been suggested that the cheap democracy of Web publishing will make it possible for anybody to publish their data, peer-reviewing be damned.