Since August, Google has been testing changes to the Quality Score algorithm in Brazil, Spanish-speaking Latin America, and Portugal that increased the weight give to landing page quality and relevancy. Google has always been focused on providing a great user experience as a search engine and this means providing the most relevant search ads to user’s search queries.
Based on the results from their trials, users are happier when the pages they’re being directed too are of better quality and relevancy and the pages of lesser quality and relevancy appear less and less in their search results (because they’re being penalised Cost Per Click and budget-wise). So Google is going to start rolling out the changes globally: http://goo.gl/fn0lK