I was searching the web for Opera version of Flashblock plugin, but I had no success so far. I found that Opera has integrated function, similar to Flashblock. To activate it follow these steps:
1. Copy this code to address bar and press Enter.
opera:config#UserPrefs|EnableOnDemandPlugin
2. Check the first checkbox "Enable On Demand Plugin"
3. Find the section save button and save changes.
Happy browsing without heavy ads with the best browser in the world! No need for additional codes and plugins!