Google will shake up the web analysis market and strengthen its key advertising business on Monday with the launch of a free service that measures the effectiveness of websites and online marketing campaigns.

Google Analytics has been developed from software acquired when Google bought Urchin, a web analysis company, in March. Urchin was charging $199 a month for an on-demand version of its product and offered enterprise installations for Fortune 500 companies such as Procter & Gamble.

The fact that this sophisticated leading product is being lent the Google brand name and being made available for free will send a chill through Urchin's competitors, who include WebSideStory, Coremetrics and Webtrends.

It may also dismay search rivals such as Yahoo and Microsoft, who lack such analytical tools to increase the appeal of their own advertising offerings. Users of Google’s main revenue driver, the AdWords service, which creates ads and keywords, will find they can access Google Analytics from within their accounts to fine-tune their promotions and increase the return on their investments.

“By making this powerful service free, we aim to give all websites – large and small – the tools they need to better serve their customers, make more money and improve the web experience for everyone,” said Paul Muret, a Google engineering director and one of the founders of Urchin.

Google Analytics software will help businesses to select and bid on effective keywords that can attract more customers to their sites when found in web searches. It can also show how well e-mail campaigns or banner ads have fared as well as indicate where changes to website designs might be needed.

Google says it is using its infrastructure to host the service. It is immediately available in 16 languages and there is free online support. Google’s decision to make the product free fits with its existing strategy. It bought Picasa, digital-image storage and editing software and made it available without charge.