In case you are wondering why your website has disappeared from Google’s search results, there is an update — or “dance” — in process, which started around May 21st and will last for another 2 weeks.
Whether your site’s ranking in search results has gone up or down, make sure to wait another couple of weeks for things to get back to normal, before you start optimizing your site. Then, study the sites that get top rankings for your keywords and check out a few webmasters forums to get an idea on the ranking criteria associated with the new algorithm.