Disable Ads on YouTube

There are a lot of ways to block ads, but with a simple command in the developer console, you can disable all ads on YouTube via an experiment.

Google frequently tries out new features with experiments via TestTube. A less advertised experiment can disable all ads on the site. Here's how to turn it on:

1. Open up a YouTube video (any will do).
2. Open up the developer console (Ctrl-Shift-J for Chrome, Ctrl-Shift-K for Firefox)
3. Enter the following code:

document.cookie="VISITOR_INFO1_LIVE=oKckVSqvaGw; path=/; domain=.youtube.com";window.location.reload();

 Boom. No more ads. Since this is something that Google is allowing, it's possible it could go away in the future, but while it works, you get a lovely ad-free viewing experience without any plugins. It even works on those pesky video ads.

Alternative

Experiments do not last forever and it is very likely that Google will disable this particular cookie eventually.  An alternative to that is Adblock Plus, a browser extension for most web browsers that removes advertisement on YouTube as well.