This is a list of "name spaces" suitable for use in tagging, and by the rel="tag" microformat. Please feel free to add to it, in alphabetical order
- One word - http://search.ebay.com/door
- Multi-word - http://search.ebay.com/door-mat (hyphen)
- International - http://search.ebay.co.uk/door (etc.)
- One word - http://www.flickr.com/photos/tags/door
- Multi-word - http://www.flickr.com/photos/tags/door_mat (underscore)
- One word - http://technorati.com/tag/cheese
- Multi-word - http://technorati.com/tag/apple+pie (plus sign)
- One word - http://en.wikipedia.org/wiki/microformats
- Multi-word - http://en.wikipedia.org/wiki/brown_sugar (underscore)
- Case sensitivity (http://en.wikipedia.org/wiki/Perry_Barr works; http://en.wikipedia.org/wiki/perry_barr does not)
- Caution should be exercised when using Wikipedia as a name-space. For example, an article about Birmingham, Alabama, tagged with a link to http://en.wikipedia.org/wiki/Birmingham would link to an article about Birmingham, England.
For place names.
- One word - http://wikitravel.org/en/London
- Multi-word - http://wikitravel.org/en/East_Grinstead (underscore)
- A tag using, e.g. http://wikitravel.org/en/Newcastle will link to a disambiguation page.
- See also rel-faq
- rel-tag advocacy - encourage others to use rel-tag.
- rel-tag-spaces - sites suitable as using as targets for rel-tag links.
The rel-tag specification is a work in progress. As additional aspects are discussed, understood, and written, they will be added. These thoughts, issues, and questions are kept in separate pages.