I find my most of the keyword possession are displace in this week. Most of the keyword are down for this place. What you think about this update.
Violating Google’s guidelines can be one reason. Here’s Google’s Matt Cutts helping you with a few more: http://www.youtube.com/watch?v=gx04qNrCbnk&feature=player_embedded#
If you violate the rules of google then you will automatically punished by google and it can be down your keyword or anything else.