Google has released a browser add-on that will stop information being sent to Google's Analytics service, which web sites can use to collect data about their visitors.

Google said it developed the tool "to provide website visitors with more choice about how their data is collected."

Web site owners can incorporate Google's Analytics JavaScript code on their site to collect data such as when a person visited a website, if the person has been there before and the search terms a person used to find the site.

Analytics creates a cookie on a person's computer. Cookies are small data files used to record information about how a person interacts with a website.

Google's new tool, the Analytics Opt-out Browser Add-on, tells the Analytics JavaScript that information on the website visit should not be sent.

Google's motivation in creating the add-on is likely defensive in case it comes under pressure from regulators over privacy concerns, said Daniel Brandt, president of the not for profit Public Information Research group, and who runs the Google Watch website.

Analytics has come under scrutiny in Germany regarding whether the service violates data protection laws in the country.

"The reason is that there's no notification to the end user of the data that's getting collected by websites in Germany that are using Analytics," Brandt said.

Like all cookies, the cookie for Analytics is created automatically unless the user's browser is set to refuse it. Browsers can be set to refuse cookies globally, or add-ons can be used to manage a list of sites from which cookies are blocked.

There are other tools for Firefox users that can block Analytics.

Adblock Plus and NoScript can both be set to prevent Google Analytics from receiving any information from the browser, while OptimizeGoogle blocks the Google Analytics cookie in addition to modifying other aspects of Google's behavior, including blocking Google advertisements and modifying the user ID cookie Google assigns to users of its search engine so that they can surf anonymously.

Other cookie-management tools can also block the Google Analytics cookie, but won't stop Google Analytics from receiving more general information including the IP address of the web user and the address of the page containing the Google Analytics tracking code.

Google Analytics collects the IP addresses of website visitors but does not report the full address back to the site using Analytics.

Google says that Web site operators can collect the IP addresses of visitors regardless of whether they use Analytics.

IP addresses can be used to identify a computer connected to the internet and are regarded by some privacy advocates as personal information.

While an IP address does not identify an individual user, it can be used by a service provider to identify a broadband subscriber.

The Analytics add-on does not stop Google from putting other cookies on a computer, such as its DoubleClick cookie, which tracks the web pages a person visits and then serves advertisements related to that content.

The Analytics Opt-out add-on is compatible with Internet explorer 7 and IE8, Chrome version 4 and higher and Firefox version 3.5 and higher.

So Google make and market intrusive data-collection and cookie-creation code and then ask us to trust their browser extension that they say stops it sending the data.

What's not stupid about that then?