What type of penalty is this ?

[ckissi]

Great new year. We got penalty. And I really don't know what kind.
I studied top 50 keywords and some of them keep position (about 40% of them) and others moved from positions #1 - #9 to positions on page 5, 9 or unknown.
Our most popular keyword - contained two words : "X Y" moved to page 9. But if I use keyword which contain these to words and include third word (so I search for: X Y Z) and perform search its on position #2.
Also seems that tons of minor keywords were penalyzed because traffic dropped by more than 75%.
Anybody experienced such kind of penalty ? and if so... what did you do to recover ?

[tedster]

My first suspicion is it's related to backlinks, and specifically their anchor text. This is the kind of thing sites sometimes see when Google feels the backlink profile is too unnatural or overly manipulated in some way.