A tag can be any of: Kos:tags, tikiwiki quicktags or categories, Tagyu, Furl, del.icio.us, technorati tags, header tag, footer tag or other open politics tags. The folksonomy is still evolving.

The standard tags are the GFDL corpus tags that each appear as Wikipedia category.

Yahoo's myweb2 offers tag capabilities.

A Wired article offered tips on how to tag effectively, e.g.:

  • Use combinations of simple tags rather than inventing complex ones. For instance, use tags CIA, LEAK and INVESTIGATION, instead of CIA-LEAK-INVESTIGATION.
  • Use at least two tags for each item. More tags is better (up to a point).
  • Try to think of what tags people might use to search for something and use those. For example, PLAME, ROVE, FITZPATRICK, NOVAK, TREASON, OUTING, OPERATIVE might all be good tags for an entry on the Valerie Plame outing.
  • Try to re-use existing tags.
  • Keep it simple. Don't use tags that are redundant.