I got on a fix today about ads on websites, I already use Adblock Plus as well as the Adblock Filterset.G Updater in Firefox. But I wanted to take it a step further. I adid so with the following steps.
Opened up terminal and added the following list to my /etc/hosts file.
After this you need to flush the DNS cache
sudo dscacheutil -flushcache
All set. You can of course use this on Windows/Linux and other versions of OS X. For older versions of OS X the dscacheutil command is not the same.