A detailed AV-TEST study recently revealed that although search engine
operators such as Google and Bing make a lot of effort to avoid doing so,
they sometimes deliver websites infected with Trojans and similar malware
among their top search results. Other search engines do an even worse job.
read more.......http://www.av-test.org/fileadmin/pdf/avtest_2013-03_search_engines_malware_english.pdf