If you are one of those who is wondering why your website ranking has gone down suddenly then here is the answer for your question.

Google has launched a new algorithm change where if Google finds excessive ads on above the fold; on your page layout then it can penalize your site or downgrade your website rankings in Search engines.

Google says that user want to see content when they click on a page so website which are giving lots of ads on above the fold space they are going to get affected by the rankings.

Google says that every 1 in 100 searches (1%) have got affected by this new Google algorithm change.

Google has also provided a tool to check if your site is impacted by this algorithm change you can use this tool on http://browsersize.googlelabs.com

So if you are the one who got affected & then make changes in your layout as per the Google algorithm and then resubmit your site to Google.