I noticed something strange. One of my sites got hit by penguin and dropped from page 1 to page 2 or 3 in google.de (it's a german site). It keeps bouncing back to page 1 about every 2 week and stays there for about 1 week until it falls back.
Now I noticed that on google.com/?hl=de the site never fell of page one and still has it's regular ranking.
To me that looks strange. Any info on that and what I could do to bring it back on google.de permanently?