It’s a Google official Update for Webmasters and SEO, Google Panda 4.0 Launched on may 19 2014. This update is mainly to filter the low quality content websites from the Google Search Engine Results. Due to this Google Panda 4.0 most of the low quality content sites are down from search engine results.
This update is confirmed in cuts twitter at profile that officially rolled out on May 19th 2014. Most of the webmaster got hit with panda 4.0 and also along with “Pay Day Loans” spam refresh as well.
Due to these both the updates most of the spammy queries and low quality sites are dropped around 7.5% searches
To maintain the potential site and to over ride these Google update, need to follow the ethical practice which will be added in next post for all the webmasters.