I often become confused when I publish a post on WordPress, because it offers both the tagging and categorising. Some of the confusion are caused by the two functionalities having overlapping areas, and some related to the lack of functionality. Overtime I came up with a few guielines to avoid some of these confusion, but not all of them. I want to list those rules first, and then I want to talk about a new system and explain how it can solve the rest of the problems.

First, both categories and tags offer the reader an easier way to search your writings. A review about a particular episode of an animation series may not have the word ‘animation’ in it, but tagging / categorising allows the users to search for all writing related to this topic.

Since one article can belong to multiple categories, the distinction between the current tags and categories is only that categories can have parent-child relationships. This relationship is best applied to chronological ordering (2009 series -> autumn series). A good thing about this relationship is that selecting a parent category will show all the entries in the child categories. This offers a control of granularity for the grouping of posts. Usually I won’t have too many layers of categories. Keeping it at the minimum makes the site map easier to digest, and the category section on the side bar will not be cluttered (which in term decreases the usability).

Tagging is less restrictive to users, which means it can vary greatly to the same writer even in different period of time. I am not a believer in tag clouds. because I loses my focus when I see a sea of links, most of which are seldom used/ less meaningful. I think tagging is more suited for adding keywords. I use it as the source for generating keyword meta tags.

In essence, category gives the reader a general idea of your blog (what kind of writing there are, what is the site structure). It makes it easier for one to navigate through your site. Tags on the otherhand allows users to access your article using external search engines.

However, these guidelines sill cannot fully resolve the following questions. For example:

• Deciding if one label is more appropriate as a tag or as a category
• Worrying if the synonyms should be included as a tag
• Worrying if the category section becomes bloated when adding new sections.

I thought about these question for a while, and came up with a solution. The new system I am proposing will have the table structure like the following (this is only a prototype):

Tag table:
tag(pk)

TagRelation table:
subjectTag(pk fk)
objectTag(pk fk)
relationship(pk)

Category table:
category(pk)

TagCategory
category(pk fk)
tag(pk)

First, even when I use the guidelines I mentioned above, at times it can still be difficult to decide what should be a tag, what should be a category. This can be eliminated by only allow users to enter the tags. You may want to ask: "then how can I categorise posts?" The answer is, the software will do it for you. For example, one can associate the tag "Gundam" with the category "Animation I watched". In another word, category now is dependent on tags. This means the user no longer chooses the category for each writing directly, but when tags are applied the writing will also be categorised automatically. A few good thing about this are: categories can be associate with multiple tags; the user can have a more personalised category name like "My Jukebox".

This model allows relationships other than the parent-child relationship. This is good for future extension. For example, why not add a "part of" relationship which is more flexible than the parent-child relationship (the ability to have more than one parent so to say)? We can say "Final Fantasy" is part of "SqureEnix" company, but is also part of "RPG".

Often I am feel that one particular key word is not adequate, and its synonyms are needed as well. For example I add "Final Fantasy", "FF" and even the title in Japanese as the tags, because even I use these as search terms interchangeably as well. Adding those one by one everytime can be tiring, and having those all listed in the post is messy. But if we allow the "synonym" relationship, we can just choose "FF", and the post will still be automatically be linked to the "Final Fantasy" tag.

More freedom should be given to the user on organising the categories. In this system the user can set up rules to link categories to the tags. Other than that, I think it will be useful to allow users to choose which categories to display on the side menu. This way the user will not fear that a new category will make the side menu more bloated, but instead only list out the important sections. Additional functionalities can also be offered for the visitors to drill down to see further sub categories. The same goes to tags. The user should be able to set which tags can appear in the tag cloud. Having too many items in the tag cloud can never be a good thing.