Given the ubiquitousness of Google’s services – search, maps, Gmail, Analytics - the company can collect huge amount of information about you in ways you won’t even know. Some of them are obvious, like the Google Analytics code that almost every website uses to track visitor data. That data is sent to Google’s servers and not the server of the website the tracking code is on. Although this information is anonymous, Google can use it to size up visitor’s demographic and user’s tastes worldwide, and use this information to target ads and for other marketing purpose. Other data gathering ways might not be that obvious.
Google Alarm is an extension for Firefox and Chrome, that alerts you every time information is sent to Google as you browse the web. The extension won't protect your privacy from Google. Rather, it shows just how frequently information about you is sent to Google servers. Whenever any information is sent, an air-raid like alarm sounds, and information is flashed on screen. The information displayed are the types of Google services that are being used (Analytics, Adsense, etc), and the number and percentage of the sites you've visited that send information about you to Google.
You don't have to visit a Google-owned Web site in order for information to be sent to Google. The alarm flashes on almost every site you visit. Note, that the extension doesn’t stop the information from being sent, it just alerts you when it happens.
If the sound of the alarm bothers you, there are silent versions, with visual alerts only, available as well.