NEW YORK (TheStreet) - Google said Thursday it is changing its search algorithm to improve the rankings of high-quality sites, while pushing down low-quality sites. The change, which will affect 11.8% of all search queries, is reportedly directed at reducing the visibility of content farms like eHow that have a low value add for users. Shares of Google rose 0.4% in pre-market trading Friday to $611. News Corp is kicking off its process to explore strategic alternatives for ailing social network Myspace, according to reports.