Utma, utmb, utmz cookies

From Helpful

These are primarily notes
This is probably not going to be complete in any real sense, and exists to contain bits of useful information.
The cookies named
__utma
through
__utmz
are part of Google Analytics, originally by the urchin tracking module, also by the newer ga.js.

These cookies track usage on sites that use Google Analytics.


Some details:

  • __utmz tracks where a visitor came from (search engine, search keyword, link)
  • __utma tracks each user's amount of visits, first, last visit.
  • __utmb and __utmc are used to track when a visit starts and ends to some decent time resolution (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)