Topic Maps, a standards-based technology, is a model used to organize and integrate digital information in various applications and domains. Topic maps emphasize the findability of information.
It may represent information using topics, representing concepts from people, organizations, and countries to software modules, files, and events; occurrences, representing resources of information relevant to a given topic; and associations, representing hypergraph relationships that exist between topics. They are often confused with mind maps and concept maps. However, of the three, they are the ISO standards.
Topic maps, often regarded as a superimposed semantic metadata layer, are used for indexing information resources . The indexing is often dispersed and heterogeneous. They are supported by a number of query languages, publication tools, exchange formats and development. Websites, content management systems (CMSs), knowledge portals, and social bookmaking services often use topic maps.
In a topic map, topics may be assigned one or more names and categorized in types, subtypes, and instances connected to internal as well as external content. Internal content often constitute information within a topic map itself, including data descriptions, data values, among others. On the other hand, external content may constitute resources outside the topic map, such as web pages, files, among others.
There may be a relationship (in typed associations) between topics, and are assigned semantic roles and linked to external descriptors (also known as subject indicators). You can access these subject indicators via subject identifiers, often URLs. They are central to the Topic Maps paradigm as they play a vital role in facilitating the merging tops that share one or more subject identifiers.
As such, it can be said that they facilitate the integration of disparate topic maps. Topic Maps community strongly encourage the use of stable subject indicators and identifiers publicly available, such as PSI’s and PSID’s, as they are the key to stable and more reliable data integration.
In practical applications, Topic Maps have many applications and can be used to navigate a site immensely. In some sites, the way to navigate is using tags, which may or may not include search – not a regular navigation.
Some sites use them as topic navigation in either categories or tags. They can sometimes show a level of interest, such as a blog tag cloud showing how often a tag is used. Others use them for filtering, for instance, the new Google wonder wheel which often help filter results. If done right, tag clouds have the potential to greatly enhance the usability of a site. However, if not done right, they can be an eye sore.
When designing a website, designers should not forget that topic maps are solely used to enhance the usability of a site, and not just graphical gimmick. You will often see fancy tag clouds that are just pretty but not very useful to a site.
Some examples of tag clouds that do not seem so helpful are animated tag clouds with tags moving, making it difficult to easily find what you are looking for. In addition, a tag cloud that is dynamically updated and tags resize depending on real time usage is not very useful.