This is a follow-on to my earlier post. The second interesting post to which I referred, included the following story of [presumably] unintended consequences:

When Google released their toolbar, he, like most of us, installed
it. What was different was that he installed it with all of the advanced
features (including the tracking options, which Google goes out of their
way to make crystal clear *is* tracking software). He reasoning was
similar to the thoughts you expressed below: he had nothing to hide, he
believed Google really was stripping identity data from their observations
of his browsing habits, and he did not mind having them "watch".

One day he had a firewall issue when trying to retrieve a file,
and the person who was hosting it offered to put it on a "private" (i.e.,
unlinked) page for him to grab over HTTP. He accepted, downloaded the
document, and promptly forgot about it - until this document, which had
extremely personal information on it (personal to the person *hosting* it,
not the person retrieving it) showed up on Google a short time later. You
see, the toolbar had seen him go to a web page that Google did not have,
and so they indexed it right away.

Without meaning to, the user of the toolbar had helped Google to
violate the privacy of the person who went out of his way to keep this
document private. This person knew nothing of the toolbar, and had no
agreement with Google, yet he became the unwilling participant in Google's
web cache.

The senders of email to users of Gmail are in the very same
position as our friend above: they know nothing of the agreement, they are
not participants in the Gmail program - they have never agreed to allow a
third party to access *their* private thoughts and utterances, yet they
too are caught in the middle.

The third post responded to the second.

The privacy violation isn't that google monitored the browsing (you gave
them permission). Nor is it that google indexed it (you gave them
permission). The privacy 'violation' is that private information was made
freely accessible by the owner of the information.

All three make points worth thinking about.