Is there a standard governing the __utma, __utmz etc.. cookies?

Question

Whether I log into Facebook or Twitter, I'll be bombarded with cookies of the such names as:

__utma __utmb __utmc __utmv 

What are their functions ? Is there a standard that governs how these are used on the serverside ?

Answer 1

These are cookies generally associated with Google Analytics.

See this info from Google itself.

BTW, the UTM prefix originally stood for Urchin Tracking Module, whereby Urchin Software Corp is a company acquired by Google in 2005 and which product was used as the basis for Google's initial offering in the Web Site Analytics market.