A page of mine  (http://loginhelper.com/networks/facebook-login/) was ranking in the top 10 for keyword (facebook login) and has been for at least 2 months, moving between 5th and 10th. Suddenly in the last 3 days the rank for the keyword dropped from 7th to 46th, yet none of the other keywords have been affected (they target other pages) and their ranks have continued to improve. I am trying to figure out what caused this sudden drop in the ranking of 1 page (the page has quality mainly text based content and isn't in the least bit shallow or spammy) I have been thinking perhaps a crawl or server error may be to cause leaving the page temporarily unavailable or with a big load time... Otherwise what could cause one page to drop so much so quickly whilst other pages improved their rank?