Going Back and Up Dating Old Content

i'm hearing so many people abdating their content all the time and swearing by all kinds of methods. And we have tried them all. But once you compare it the control rope, it doesn't work. So nothing happens. We don'thear the additional traffic for us from apdating content. If someone out there has tried this properly like that, and can show me that it works, i would love to know how. Because we didn't in we couldn't make it happen.