Next, use categories (= keywords, tags) to group posts into topics, in octopress.

Categories should be listed in the header of a page. rake new_post['page name'] creates a heading in the poster for doing this. To input more than one category, or a category consisting of more than one word, use one of the formats explained in following example from http://octopress.org/docs/blogging/ :

 # One category
 categories: Sass

 # Multiple categories example 1
 categories: [CSS3, Sass, Media Queries]

 # Multiple categories example 2
 categories:
 - CSS3
 - Sass
 - Media Queries

Listing Categories: Plugins

Category tree: https://github.com/matthiasbeyer/jekyll_category_tree

Category list + Tag cloud: https://github.com/tokkonopapa/octopress-tagcloud