Google uses what I search for in the ads that it shows me on different websites, and I don't want that because it will tell people what I'm interested in.
How do I stop Google from doing that? Is there an option somewhere I could set?
The easiest way to opt out from personalized advertising is via this plugin: http://www.google.com/ads/preferences/html/intl/en_us/plugin/
If you don't want to install the plugin you can set the Google Opt-Out Cookie on this page: http://www.google.com/settings/ads/onweb/
For an opt-out on multiple sites (including Google) see this page: http://www.networkadvertising.org/managing/opt_out.asp