All major search engines returned "risky" sites, including those that install adware or spyware, when users search using some popular keywords, writes DM News, citing a study from McAfee. McAfee estimates that searchers click 285 million times on "hostile sites" every month. Sponsored search results are more dangerous: on average, 8.5 percent were deemed so, compared with 3.1 percent of non-sponsored search results.

MSN search results had the lowest share of dangerous sites at 3.9 percent; Ask.com had the highest percentage at 6.1 percent. "Dangerous" sites made up as much as 72 percent of results for certain popular keywords, such as "free screensavers," "digital music," "popular software."