Many youtube videos don't play with adblocker (tried almost all of them) extension. Disabling adblocker will allow videos to play. This behavior is the same on Windows and on Linux also. However, in google's chrome browser (using the same extension) videos will play normally without ads. So, it is NOT adblocker's extension problem, IT IS a firefox problem. Remember I tried all available adblockers and problem remains, while in chrome the problem with same adblocker extensions does not exist. This is a deal breaker for me. I really want to use firefox, but this is a deal braker for me. Returning to chrome, until this problem is fixed.