Graphical browsers serve as overview displays for large bodies of information, especially in a hypertext system. NoteCards from XEROX and gIBIS from MCC both provide these browsers with which users can scroll through the entire network as well as rearrange the nodes. Both systems provide facilities to view the contents of the browser at different levels of detail. For large networks, the highest level of detail about the structure will be provided. The user can zoom in to see any portion of the browser in detail but cannot look at the details of the entire network because of screen space limitations [Utting & Yankelovich, 1989].
Graphical browsers help reduce disorientation by providing a two-dimensional spatial display of the hypertext network. They also help minimize cognitive overhead by showing a small part of the network. They also provide an idea about the size of the network which help users estimate the number of nodes and links in the system. If the user needs an idea about the contents of a target node prior to visiting it, some kind of a "peek" mechanism can be provided. Though general browsing is a low cognitive load operation, it is inefficient for directed search tasks or fact retrieval. Also, a graphical browser itself can become a tangled web if the hypertext network is large and if the display has to be updated because of dynamic changes in the network.