If you avoid pre-roll ads in YouTube or ad banners below the video clips, then get one of these five (5) free adblockers extensions.
1. Block YouTube Ads
This free blocker removes all video ads before and during videos, also gets rid all those ads that pop at the bottom of the screen while the video is playing.
It is easy to install and it works for the three major browsers: IE, Firefox and Chrome.
Get it here: http://download.cnet.com/Block-YouTube-Ads/3000-7786_4-75742538.html
2. YouTube Ad Skip
Get it here: http://sourceforge.net/projects/youtubeadskip/
3. YouTube AddsFree For Opera
Get it here:
https://addons.opera.com/en/extensions/details/youtube-adsfree/?display=en
4. AdBlock Video For Firefox
This tool gives the control when you want to block the ads which you consider as excessive or annoying. There is an On and OFF option.
It works well with sites which include: CBS, CNN, NBC, Fox, Hulu, DailyMotion, etc.
5. AdBlock For Chrome
This adblocker extension is able to block all advertisements on YouTube, Hulu and even Facebook.
Get it here: https://chrome.google.com/webstore/detail/adblock/gighmmpiobklfepjocnamgkkbiglidom
With one of these YouTube ad blockers, you don't have to wait for another 5 seconds to click to remove the ad.