Opera 11 coming soon with extension support

Opera next browser version 11 is coming soon with extension support just like other browsers chrome extension and firefox add-ons. Developers can write extensions to extent the functionality using  open standards (HTML5, CSS, JavaScript) and supported APIs. The extensions are based on W3c Widget specifications.In the first release of Opera Extensions focusing on open web standards. The alpha release supports injectable JavaScript, callouts, certain UI items and a basic Tabs and Windows API.

Source : Opera 11 will have Extensions