"IE9 has just released around the world," a booming voice told a cheering crowd at 11:00 pm Monday (0400 GMT Tuesday) in the Austin City Limits Live concert hall where a launch party was being held.
Internet Explorer 9 (IE9) was available for download in 30 languages at beautyoftheweb.com.
"Things are about to change," Microsoft corporate vice president Dean Hachamovitch said just hours earlier at a press conference at the South By Southwest Interactive technology festival here.
"We took a dramatically different tack," he continued. "It's a really good day for the Web."
IE9 is built to make the most of Microsoft's latest operating system, Windows 7, as well as graphics processing chips that can power videos, games and graphics.
The long list of partners that have adapted websites to IE9 includes Facebook, Twitter, Pandora, Hulu, and Yahoo!, according to Microsoft.
"We have worked with partners reaching a billion active Internet users," Hachamovitch said. "All of these partners are using IE9 to make a more beautiful Web, starting today."
More than 40 million copies of IE9 have already been downloaded as part of the process leading up to its official release, according to Microsoft.
Microsoft showed off a lean, muscular new Internet Explorer crafted to spotlight slick websites and beat back competition from Firefox and Google.
Microsoft director of web services strategy Ari Bixhorn booted up an Apple MacBook Pro laptop running the latest version of Firefox for a side-by-side comparison.
A laptop powered by Windows and using IE9 smoothly zipped through cascading images illustrating top tunes at a radio station website while the competition appeared to be much slower.
Once a website is reached, the IE9 browser seems to almost vanish to spotlight the content.
"The browser is the stage and the websites are the stars of the show," Hachamovitch said during an earlier demonstration.
The browser is included in Windows software, and the operating system remains at a core of Microsoft's software empire. The Redmond, Washington-based technology colossus claims more than one billion Windows customers.
IE9 promised to be another hit release for Microsoft, which has had market success with the Windows 7 operating system and the Kinect motion-sensing controller accessory for Xbox 360 video game consoles. (AFP)