For what does Ubuntu use Zeitgeist?
I am using Ubuntu right now and found out that Ubuntu desktop (so unity) work with Zeitgeist core and much more.
Zeitgeist is a German word meaning approximately: "the spirit of the times" reference
In the context of Ubuntu, it is a software package that remembers your activities to try and assist in narrowing down what you want to do without having to tell the computer as explicitly.
It is no more associated with the movie "Zeitgeist" than Hollywood is associated with the production of boards made from holly bushes.
Merged in from a comment (thx @izx): Something you might want to read