From Adblock Plus:
The best adblocker for Opera removes all the annoying ads immediately. Adblock Plus for Opera blocks all obtrusive advertising on your screen for free! The most popular add-on worldwide with over 60 million users is now available for your Opera browser! Default settings enable some non-intrusive ads, which adhere to our criteria, to be seen. This supports free content and encourages better ads, but if you'd prefer to see no ads you can opt out easily. Adblock Plus for Opera removes: *all annoying ads from your browser. *advertising from your Facebook and Twitter feeds. *pop-ups. * Banners. *Youtube video ads, including 30-second, pre-roll ads. Additional privacy and security features, like malware and tracking protection and blocking social media buttons, give you control over your browsing experience. In addition, the icon in your browser indicates how many ads you have been blocked on every site you visit. Clicking on the icon shows more options, including allowing you to block page elements. Adblock Plus is an open source project supported by volunteers from all over the world, currently available in over dozen languages and with over 40 potential filter lists. Adblock Plus is also available for Google Chrome, Mozilla Firefox, Internet Explorer, Safari and also for Android. It works perfectly on both Windows and Mac OS X.