Comment on Fresh Content SEO by Viachslav.

Fresh SEO Content If I were Google, I would consider suspicious websites whose pages are constantly changing (being refreshed as you say). I would think something blackhat is happening. Normal pages do not change their core content. They only grow bigger with comments, there may be change in layout. But good valuable article remains the same. So from common sense perspective it’s bad to have your content refreshed.

But of course this is only hypothesis which needs to be tested.