Main feature is security. First of all the new antiphishing system. This browser has a real-time (this means no black list to be preloaded at start up) fraud protection toolbar. Opera supports Secure Socket Layer (SSL) versions 2 and 3, and TLS and it offers automatic 256-bit encryption, the highest available security of any web browser. Opera displays security information inside the address bar. By clicking on the yellow security bar you get access to more information about the validity of the certificate.
Moreover Opera gives you detailed control of what cookies to accept and reject, such as allowing for different set-ups for different servers. Opera can be configured to clear the history and cache when exiting, to protect your privacy. Any kind of private data can easily be erased. You can also remove ads or images if you feel like, simply right-click (or CTRL-click on the Mac) on the Web page and choose "Block content".
Another feature is the client BitTorrent, you will not need a separate BitTorrent application to download large files a new customizable system allows you to select the content and you just click a torrent link and start the download.
You can also easily add your favorite search engines, just right-click on the site's search field and select "Create search" from the menu.
You can also use thumbnail preview by hovering your mouse on any tab and see a thumbnail preview; this makes it easy to have many tabs open at once in Opera.
Opera comes also rich with widgets: small Web applications like multimedia, newsfeeds, games that make your desktop experience more fun. You can use the Widgets menu to discover new widgets and access your favourites.