Opera Software has released Opera 9.

The web browser is available for free download, in over 25 languages, for Mac, Windows and Linux, from the company.

The new software offers built-in BitTorrent support and a range of widgets (small web applications). It also maintains the security and speed "millions of Opera fans have come to expect", the company said.

Widget developers can create widgets using open and common web standards including JavaScript, CSS, HTML and SVG, and technologies like AJAX.

"For Opera 9, we worked hard to push the limits of what people expect from a browser, with increased speed, new web standards support and innovative features such as widgets and BitTorrent," said Jon von Tetzchner, CEO, Opera Software. "Even though we shaped this browser for the future, we have the powerful features people want and need for their surfing today. I truly feel Opera 9 has something for everyone."

Opera's security and pop-up ad blocker have been improved, and the browser's appearance can be customised using "skins".

The software also includes tools to make it easier for sites to develop for emerging open standards: built-in Extensible Rendering Architecture (ERA) helps developers make sure their sites work well on any web-connected device, from mobile phones to Nintendo's Wii.

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