An important application of the showme command is to provide hypertext help for other software packages.
In this situation, the help information would be contained in one or more hypertext documents and the controlling software would invoke the showme command to display the required part of it on demand, the information being selected by giving an appropriate cross-reference label. The person reading the displayed information can then explore any hyper-links within it to gain further information. These could point at other documents you have linked the help documents against or, indeed, anything else on the WWW.
When designing a graphical user interface, help information can easily be made "context sensitive" by setting the cross-reference label according to the task being performed (e.g. which window is active) and invoking showme when a "help" button is pressed. In fact, with a dedicated WWW browser, one might even consider displaying the information automatically as the task in hand changed, without waiting to be asked.
By going via this HTX interface, the controlling software is insulated from changes in the way the help documentation is organised and indexed. It also need not concern itself with how to communicate with the WWW browser. In some cases, however, you may want your software to handle the display of help information yourself. You can do this by using the -n switch on the showme command, thus:
showme -n help_document subject_label
This prevents showme from displaying the document. Instead, it simply writes the URL for the part of the document you requested to its standard output. Your software can then read this and handle it in whatever way you choose.