LOL well... I have read this on an IT/marketing forum before I got into IM when I was on that forum for IT
Anyways google got smarter. If every kid can write an http tags parser don't u think google guys can too? I mean, there are like 1000s of them, at least one good programmer?</sarcasm>
After the hidden content thing worked, there was another method that I'll share here, used to work for a while, not sure if it still does.
Putting the content and hiding it from CSS, then making it invisible with CSS for real visitors. Playing with css was fun, making the text so bad it looks like background image, transparent 99%, on the bottom of the page. Very small images all over the page with long ALT tags.
Some are just theories, never tried them, feel free to do so if u think somethin would work