Why make a directory?

Collection – This could be as simple as making a list. The most common directory in use is the Contacts list on your smartphone (people and phone numbers, sorted in alphabetical order)

Curation – Seeking to list the “best of” resources for a topic

Examples

Feed Handbook (by Andy Sylvester) – Information on feeds of many types (RSS/Atom/etc)

Radio Userland Resource Directory (by Andy Sylvester) – created in 2007! (have to hover in front of the entry to see the link, need to update this sometime…)

Bob Dylan Bibliography (by Ron Chester) – created in 1996!

Indieseek XYZ (by Brad Enslen) – A human edited Indieweb directory

href.cool (by Kicks Condor) – in the style of the old DMOZ and Yahoo directories

Tools

Web page – make a ordered list or an unordered list and – voila! – a directory is born

Hugo – static site generator, used for the Feed Handbook above

OPML – XML file format used for subscription lists for podcast players

OPML Editor (for editing OPML files)

Little Outliner 2 (for editing OPML files)

WordPress – use of categories could create a directory structure, also there are many plugins to support creating directory websites (like Yelp, etc.) or simple directories