Abstract: Techniques are discussed whereby hyperlinks that exist in an on-line document can be automatically updated (re-linked) when the location of the document to which a link points changes. In one embodiment, the administrator of the on-line document is notified by E-mail when a link destination pointed to by that document has changed. Comparison of the old document content to the new content, if any, is used to facilitate a determination whether to automatically re-link or remove the appropriate hyperlink. In alternate embodiments, receiving sites or trusted third parties are authorized to update links to documents on the receiving site contained in documents on a feeding site.

Abstract: A graphical user interface permits navigating through a plurality of stacked window layers or image planes. In one form, moving through one image plane to an image plane below simulates pressing on an elastic membrane until it bursts. In another form, worm holes are used to access selected layers at different depths. In another embodiment, a property analogous to thickness, is associated with an image plane and the amount of time or force required to pass through the image plane is controlled as a function of thickness. In yet another form, a force feedback input/output device having three degrees of freedom is used to give a user the feel of physically penetrating through plural stacked layers.

Abstract: A graphical user interface permits navigating through a plurality of stacked window layers or image planes. In one form, moving through one image plane to an image plane below simulates pressing on an elastic membrane until it bursts. In another form, worm holes are used to access selected layers at different depths. In another embodiment, a property analogous to thickness, is associated with an image plane and the amount of time or force required to pass through the image plane is controlled as a function of thickness. In yet another form, a force feedback input/output device having three degrees of freedom is used to give a user the feel of physically penetrating through plural stacked layers.