Implement labels and contexts for cross-correlating information by assigning tags to headlines. Every headline can contain a list of :tags:.
normal words containing letters, numbers, underscores (_), and ampersands (@) delimited by colons ‘:tag:’. They can be stacked (called a list of tags): ‘:tag1:tag2:’
==> See Tags
org-set-tags-command
C-c C-ccall org-set-tags-command when on a headline; activate changes to in-buffer
settings
All subheadings inherit tags from parent headings
Assign tags to all headings in a file
Name default tags to choose from for a file
disable persistent tags alist