Search engine Google Inc has announced it will launch a free, Web-based e-mail service to compete against popular services from rivals Yahoo! Inc and Microsoft Corp.

　　Google's service, called Gmail, will include a built-in search function that will let people search every e-mail they've ever sent or received.

　　According to company executives, users will be able to type in keywords to sort e-mails or find old messages.

　　And it will come with one gigabyte of free storage - more than 100 times what some popular rivals offer and enough to hold 500,000 pages of e-mail.

　　But to finance the service, Google will display advertising links tied to the topics discussed within the e-mails.

　　For instance, an e-mail inquiring about an upcoming concert might include an ad from a ticket agency.

　　For now, Google is opening the service only to invited users but expects to make it accessible to everyone within a few weeks, Google co-founder Larry Page said in an interview.

　　Officials at Yahoo and Microsoft's Hotmail division declined to comment.

　　But analysts said that Google - whose technology is behind nearly four out of every five Web searches - could shake up the free e-mail market, which includes Yahoo and Microsoft's Hotmail.

　　Industry analyst David Ferris said Gmail is a logical extension of the world's most popular search engine.

　　But he said Google may run into trouble if it eventually tries to charge for e-mail.

　　The company would not provide details of its pricing strategy, but rivals have kept stripped versions of e-mail free and asked users to pay annual fees up to US$30 or more for extra storage and spam protection.

　　"I know that companies offering free e-mail are very frustrated because the consumer expects it will stay free - they simply will not pay," said Ferris, president of San Francisco-based Ferris Research.

　　"Although there's a clear tendency for these free services to offer for-fee extensions, users are very resistant to taking them up.

　　"The level of adoption is very disappointing."

　　(The Associated Press)