But for those who don't:
This is an awesome one, go to any website, click on the "Goggles" toolbar and you can scribble or write any message on any website.
Go to this site http://goggles.sneakygcr.net/
And drag "goggles" to one of your bookmark tabs. (will only work in firefox)
There are some great hidden messages appearing on so many sites.
Have fun!!
