Mailing the story:

Google Inc., the most-used Internet search engine, introduced free software so advertisers can track how often Web surfers click on ads and then buy their products.

Google Analytics also will let customers see how users move around an Internet site and whether they produce a sales lead, said Richard Holden, a product management director.

The new features heighten competition for companies including WebSideStory Inc. that offer rival software. The move also shows Google's ability to use its surging ad business to offer for free a product it once priced at hundreds of dollars.