Yahoo — not taking sides in the growing rivalry between Apple, maker of the iPhone and other "i" devices, and Google, developer of the Android operating system — is putting some of its most popular services on both mobile platforms.

The Sunnyvale Internet giant on Thursday launched e-mail and instant-message apps for smartphones running its Mountain View rival's Android software. Yahoo also is releasing a new search widget for Android phones.

As for Apple's devices, Yahoo has revamped its news and mail websites using HTML5 technology for the Cupertino company's iPhone and iPod touch.

"We're making it easier than ever for consumers to access fast, reliable and feature-rich Yahoo experiences across some of the fastest growing platforms in the market," David Ko, a Yahoo senior vice president, said in a statement announcing the new smartphone services.

El Segundo tech researcher iSuppli noted in a report this week that it expects Apple to ship 42.6 million iPhones this year, including 21.7 million iPhone 4s.

However, as Apple struggles to keep up with manufacturing problems and consumer demand, phone buyers are turning to other options such as HTC's 4G Evo and Samsung's coming Galaxy handsets, "which carry the increasingly popular Android operating system from Google," said iSuppli senior analyst Tina Teng.

Apple stock closed Thursday at $248.48, down $3.05, or 1.2 percent. Google was at $439.49, down $5.46, or 1.2 percent. Yahoo was up 25 cents, or 1.8 percent, at $14.09 after its board approved $3 billion in stock buybacks over the next three years.