We were ranked on first page among top 5 position a year ago for most of our pages. On one fine day, google decided to drop us from the results although google keeps indexing our pages. Google index our pages regularly but doesn't show them in its results. All google traffic we receive is for our own site name and its variations. I wanted to know - how do we know if google has panelized us. Why has google panelized us ? If they have panelized us, what can we do to get out of it ? Also I wanted to know if any tool will help me identify such thing. We have not done any link building. Our site page rank is 4 (it was 5 few months ago). All we did was on page optimization. Thanks for your help!