(Since this post is kinda long I'll make the important parts bold.)
A wile ago I found out about this really cool thing called a HOSTS file. Basically what they can do is redirect certain urls / IP address from coming in and out your computer. This file can be used to block ads, URLs, and other malicious stuff found on teh Interwebz. (a virus or hacker can use this to redirect you to bad websites too)
One of the problems I found with it though is that if you want to watch a TV show, like from NBC or hulu or something, it wouldn't show! I was wondering why. Then it hit me. Its because places like NBC and hulu use outside advertising in the little 30 sec. commercials that are shown. And the shows won't show on NBC until the ads are.. well.. shown =\. Hulu will show them though. So, how can you watch something if it's being blocked?