Internet Explorer 9, unlike previous versions and many competing browsers, pushes itself into the background.
"People go to the Web for site, not the browser," said Dean Hachamovitch, general manager for IE, at a press event in San Francisco. "Today Web sites are boxed in, the box is the browser."
IE9 is available in a public beta, or trial version, in more than 30 languages. Many of the world's most popular sites including Facebook, Amazon.com, Time Warner Inc's CNN, eBay and Twitter are taking advantage of IE9's new features.
The browser has become one of the most important programs on a PC. As people watch more video and use sites such as Facebook, Twitter and YouTube, browser makers are making their latest versions quicker and better at handling graphics.
Microsoft is promising a faster, cleaner, more secure version of its browser, one that will support evolving Webtechnologies, such HTML5, a standard for presenting content.
It is also more tightly integrated with the company's Bing search engine, which the company hopes will begin to eat away at the dominance of Google.
In IE9, the rendering of graphics and text has shifted to the graphics card from the CPU, accelerating speed and visuals. As a result, Microsoft said sites will look and perform more like applications that are installed directly on a PC.
IE9's tight integration with Microsoft's Windows operating system, which runs on most of the world's PCs, enables IE9 to use a computer's hardware in a way that rival browsers cannot, said Forrester Research analyst Peter O'Neill.
"This is going to make the Windows platform more attractive, and Microsoft hopes, help stop people from leaking away to other browsers," he said.
IE has been the market leader for many years, but has been losing share to Mozilla's Firefox and Google's Chrome.
IE had 51 percent of the worldwide browser market last month, according to StatCounter, compared to Firefox's 31 percent and Chrome's 11 percent. Apple Inc's Safari and Opera Software's browser had about 4 percent and 2 percent.
