Zim - A Desktop Wiki
Zim supports the use of tags to organize pages. Tags are keywords or labels that are used to categorize pages.
Tags can be used anywhere in a page using the "@" prefix. Like this: @example @tags
Tag names are case insensitive. In addition to letters, they can also contain numbers and undescores.
To find context based on tags you can use the Search dialog. For example to find all pages tagged with "@example" you can search for "Tag: example" or just for "@example". Since tags are cached in the index, this search is much quicker than a full text search for random words.
There is also a plugin that will add a tag cloud and a page index organized by tag in the side page, see also Plugins:Tags