Utma, utmb, utmz cookies

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Revision as of 14:12, 17 September 2011 by Helpful (Talk | contribs)

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These are primarily notes
It won't be complete in any sense.
It exists to contain fragments of useful information.

These cookies track visits on sites that use Google Analytics.

The cookies named
__utma
through
__utmz
are part of Google Analytics, originally by the Urchin Tracking Module, and also by the newer ga.js.


Some details:

  • __utmz tracks where a visitor came from (search engine, search keyword, link)
  • __utma tracks each user's amount of visits, and the time of the first visit, the previous visit, and the current visit (presumably partly for double checking of this information).
  • __utmb and __utmc are used to track approximately how long you stay on a site: when a visit starts, and approximately ends (c expires quickly). If you look at cookie state changes (e.g. using firecookie), you will see these change regularly.

Also:

  • __utmv is used for user-custom variables in Analytics
  • __utmk - digest hashes of utm values (verify)