Signposts on the digital highway: The effect of semantic and pragmatic hyperlink previews

In this article, the effect of a local, content (as opposed to structure) oriented navigation tool is investigated, i.e. mouse-over hyperlink previews. A usability experiment is described in which three groups of participants were exposed to three different versions of a website: without hyperlink previews, with content oriented, semantic previews, and with task-oriented, pragmatic previews. Participants were asked to execute search and recall tasks, and to evaluate task and hypertext. The results showed a decisive overall advantage for previews in terms of efficiency, but no effects on effectiveness or appreciation. Although semantic and pragmatic previews did not differ significantly, a post hoc analysis showed a learning effect of pragmatic previews that was absent in the semantic preview condition. It was concluded that previews fit in with the step-by-step goal orientation of hypertext users. Once users are acquainted with them, pragmatic previews speed up decision making.Apart from the experimental part, the article surveys research into the usability of navigation tools, thereby focusing on the analysis of navigation tools. The bottom line of this review is that most navigation tools as they are used in the experiments provide users with different types of information, e.g. local vs. global, content vs. structure oriented. This complicates the unequivocal explanation of their effect and may explain, together with user and task differences, the variety and inconsistencies observed in the results.