This has the potential of being just the nightmare people were trying to avoid with a comany that claims to 'first, do no evil'. While I'm glad that they are resisting the subpoena just on the grounds that it's an invasion of privacy, if google looses this one, there is the potential that entire search histories could be tied back to the user (including the age AND name, in contrast to some of the earlier posts suggesting they would never get any useful demographic information). If you have a gmail account, and you 're signed in, google is keeping tabs on your specific search history.
I actually still hold on to the (perhaps naive) feeling that google's heart is in the right place for the most part, though seeing the billions of dollars in cash might sway things a little. If google loses though, millions of people's search histories, and perhaps, depending on the wording of the subpoena, demographics, if not names along with them.