I have done tricks to block them in addition to the adblocker for Firefox. I have had some sites detect my adblock and completely refuse to show the video etc. Others there is a black screen for how long the ad would be running for and then the video plays. I too tried to blacklist URLs as a means to block ads and they got smart using dynamic links that continually change and so the blacklist method doesnt work anymore for me.
My one friend is recording shows online that have commercials associated with them and if its an hour show etc, walk away for an hour and come back later and play the video capture and he can fast forward over commercials this way same as a DVR for Cable TV etc. It doesnt eliminate the commercials, but the ones that last longer than 10 seconds, he can just look at the time stamp and move the slider 10, 20, 30, or 45 seconds forward to skip over time wasting commericals and it only took 2 seconds to move the slider.