In a move announced Monday, Yahoo opened its mobile platform so outside programmers can develop applications for Yahoo pages accessed on mobile handsets. Yahoo hopes the mini-applications, known as widgets, will help attract more on-the-go users, which will bring the company more money from advertising.

The company also unveiled a redesigned home page for mobile phones that includes more content and enables visitors to designate material they want highlighted.

And it released an upgrade to its ''Go'' software that is supposed to facilitate Web surfing on mobile phones.

Yahoo believes its Go software gave the company an early advantage in a battle to deliver more advertising and Internet services to the 3 billion mobile phone subscribers.