"pipe links" are a variant form of hard links. while a hard link to the node "wikipedia" would look like codice_1, the pipe link allows the author a greater degree of freedom without restricting what nodes can be linked to. for example, one could write "codice_2" the sentence looks like this to the reader: "online encyclopedias have started to become common sources in my students' research papers." rolling over the phrase with the mouse (e.g. "online encyclopedias") shows the hidden content (in this case, "wikipedia") as the link's title.