Yahoo has launched its own version of Microsoft's upcoming Internet Explorer 7 browser with Yahoo Search built in. 

The move is seen as an attempt by Yahoo to strengthen its position in a search market dominated by Google and Microsoft.

The beta 2 version of Yahoo IE 7 is not a revolutionary product. It offers fewer features than the current Yahoo Toolbar for IE 6, and its much-vaunted tabbed browsing is already available in Mozilla's Firefox.

Tabbed browsing and built-in anti-spyware are included in non-customised versions of IE 7 or Microsoft Windows Vista. The Vista Beta 2 Customer Preview Program is now available to download online, or can be ordered on DVD. 

But for Yahoo, its IE 7 is more than just a collection of tools. The customised browser is a defence against industry giants including Google, Microsoft and Firefox.

The more users who download Yahoo IE 7, the fewer users Yahoo will lose to Google and Microsoft, apparently. Google remains the world's most popular search engine, and Microsoft's search is built into IE 7 by default.

Google recently attempted to have the IE 7 search box changed, arguing that Microsoft's default inclusion of its own search engine contravenes anti-trust laws. But the claim was thrown out by the US Department of Justice.

Industry analysts are now debating whether Google will launch its own customised IE 7. Google launched the first search toolbar for IE, but it now has a close relationship with Mozilla, and may prefer to boost the fortunes of IE rival Firefox.

Any developer or partner is free to create their own version of Microsoft's upcoming browser using the Internet Explorer Administration Kit.