The thing that troubles me about this is that, even if Google are planning to "do no evil" (and making a lot of money isn't necessarily totally consistent with that), once the data is collected (who is searching for what, and how often, and what links they ultimately follow), who can say for sure that one day this won't happen:
- Google are served with a Court order to hand over all their records (eg. "to catch terrorists")
- The files are just leaked - remember WikiLeaks? Any security system will eventually be broken.