This means that a site may have following things: Sudden Drop in traffic Sudden Drop In ranking in many folds. Site is removed fully. Check at http://www.google.com/safebrowsing/diagnostic?site=mysite.com
Some time Google change its algorithm and so many sites loose back links, PR, And even ranking so all the time it is not true that Google put a penalty. Google often applies backlink devaluation to links from various sources that it considers spammers are exploiting to artificially raise the ranking of their sites this also effect PR and ranking.
If you suspect a Google penalty, it first makes sense to check whether any Google algorithm changes have been made which could be the cause of the problem. SEO Forum posts reflecting algorithm changes usually appear on the SEO Chat FORUM.
Send Webmaster Reconsideration Request in the Google webmaster tools and requested a review of our site, clearly telling them that no above activity is there after correcting the website like paid text links or hidden links are currently sold on our site. Assured them our site was compliant with Google quality guidelines. Still if you have any problem come to us. We will reinstall the site from 3 to 10 days depending upon Google penalty. Some time you get de listed or google penalty is there and you do not know why. Come to us. For GUARANTEED RECOVERY OF WEBSITE mail at email@example.com