Google Search Engine , the most-used search engine on the World Wide Web, has been successful primarily because of a patented algorithm called ‘PageRank’ that helps rank web pages that match a given search string. The PageRank algorithm  analyzes human-generated links assuming that web pages linked from many important pages are themselves likely to be important.
To harness this phenomenon of this popular search engine an industry of professional consultants for search engine optimization  have emerged to influence their clients’ websites’ Google rankings. Although Google has published specific guidelines  for website owners who use optimization consultants to raise their rankings, some have devised unethical means  to generate links  to influence the search engine algorithm. And Google has taken these complaints seriously.
Google’s recent algorithm change (called Penguin) affected low quality SEO/link building services, much of which was being outsourced by the US to countries like India. A report  claims that this update has impacted employment in Mumbai, Delhi and Bangalore, and internet workers staged protests. However this information has not been verified by other sources.
There are many discussions in the industry on how to recover from  the change in algorithm. Experts  say that Google's new algorithm has wiped out sites engaging in webspam and black hat SEO tactics.
In a guest post Ajay Verma, co-founder of a price and product comparison portal, writes in Medianama :
Google’s new proposed metrics aren’t changing the platform at large but only the perception. It also helps filter some junk publishers. Even though ‘Clicks on Ad’ is perceived to be a transparent metric, reports  suggest a ~20% fraud rate here. One can well imagine the faith of impression based spends. Hence the clean up was required.
This is a welcome move from Google. A small step with the change in metrics will prove to be a giant leap in online advertising.