The category structure of the site is hierarchical, mandatory, and exclusive, meaning, that an article must have only one category, then one parent category, and up the branch to the stem of the tree. Categories are the primary organizing system of the website.


Tags are the main labels of the site, its secondary taxonomy, organized hierarchically.

Difference from Categories

Unlike categories, tags are not exclusive: one article can be labeled with multiple tags from different branches of their hierarchical tree.


These labels are the third organizing system on the site. Metatags are the part of the metadata of an article, readable by search engines. It is used for less common keywords and terms. They are used to provide a quick summary of the content and to link similar articles.


Specific keywords assigned to articles in metadata according to the topics, listed alphabetically. Meta-tags are additional to categories and predefinedstructured site tags. This list includes links to articles.

Descriptive keywords - general labels, meta-tags.

Additional keywords used in metadata with meta-descriptions.