This model has many usages in PardallMarkdown:

• Taxonomies/categories are saved as Link. A taxonomy Link also has all of its Post posts embedded into :children (notice that the post content is set to nil when the post in emdebbed into a Link).
• Post links for navigation and hierarchisation. A Post own Link also contains links to the :previous and :next posts of the content tree.

Special notes:

• :sort_by and :sort_order: the sorting rule to sort a taxonomy's posts. Used only by links of the type: :taxonomy.
• :index_post: the parsed _index.md file as a Post. Can be used when showing the archive page of a taxonomy (alongside the taxonomy Link.children posts). Used only by links of the type: :taxonomy.