The content in my site's home page very old. I have not changed and it has been the same for past 2 years. I was ranking very well for one of the keyword. My site will be in 3rd position. But after the recent panda update, my site's ranking went back to 2nd page and now it is in 9th position. Every time i check its position changes. Do i need to change my site's home page content because of the algorithm change. But my site does not have copied content. Help me in retaining my site's keyword to original position.