The mobile content service which Yahoo previewed at Mobile World Congress in February launched today across eight countries, available both as an iPhone app and a mobile content site optimised for 300 devices ‘with HTML-enabled mobile browsers’.

Yahoo Mobile, available at http://new.m.yahoo.com or from the App Store, combines what you’d expect from Yahoo’s services — search, news, social networks and email — with other web content which users can select to personalise their experience. The ordering of that list of services, taken from the official press release, is a clear indication of Yahoo’s priorities.

The service and app launched in the UK, Germany, France, the US, Canada, India, Indonesia and the Philippines, with additional localised versions expected to launch over the next several months.

Yahoo says the launch, which comes a scant eight months after Google launched its iPhone app in the UK, is all about continuing the company’s mobile leadership and capitalising on its market potential, which it plans to do through rich media display advertising that will encourage user engagement, so for example, allowing users to send ads to a friend or click to call the advertiser directly.

So far the app’s received a lukewarm response on the App Store, garnering a mere 1.5 star rating (though of course, only six people have rated so far) and complaints about the speed of the app over GPRS and loads of ‘page not available’ error messages.