Despite a 12% decline in the overall chance of clicking through to a risky site, the study estimates that consumers click through to risky sites more than 268 million times each month. 

Key findings:

• On average, 4.4% of search results link to risky Web sites. AOL returns the safest results with 3.6% of results rated red or yellow by McAfee SiteAdvisor.  At 5.1%, Yahoo! returns the most results rated red or yellow. 
• 8.0% of sponsored results are rated red or yellow - almost three times the 3.0% of organic results rated red and yellow.
• 8.0% of results for adult terms are red or yellow vs. 4.1% for non-adult terms.
• 41.4% of red or yellow sites exhibit poor e-mail practices, 24.5% contain risky downloads, 26.8% are scam sites, 32.3% link to other risky sites and 3.0% contain browser exploits. Many sites posed multiple dangers.
• 3.0% of red and yellow search results contain browser exploits - particularly serious threats which can damage a PC once consumers merely browse to a site. 
• Just under one third of risky results are due to sites aggressively linking to other risky sites. Many sites exhibit multiple dangers.
• Overall riskiness of search engines declined by 12.0%, while the percentage of red and yellow sites in sponsored ads decreased by almost 6%.

Risky Searches

• 14.5% of search results for searches containing the word "free" link to sites rated yellow or red. 
• 23% of "tech toys" category in Google Zeitgeist search terms  are rated red or yellow by McAfee SiteAdvisor.  The top five most dangerous Google Zeitgeist categories include:

The study was conducted by compiling a list of approximately 2,500 popular keywords derived from lists of common searches from the search engines themselves and other industry sources. The first five pages of search results for each keyword were then analyzed for each of the five search engines. The study was co-authored by Ben Edelman, noted spyware researcher and an advisor to McAfee. 

McAfee SiteAdvisor adds red, yellow, or green ratings to sites and search results based on proprietary tests of sites representing more than 95% of the trafficked Web. Red ratings are given to risky sites that fail one or more of McAfee's tests for adware, spyware, viruses, exploits, spammy e- mail, excessive pop-ups or strong affiliations with other red rated sites. Green rated sites passed each of these tests. Yellow ratings are given to sites which pass McAfee's safety tests but which still have nuisances warranting a user advisory. To see a full report on the McAfee search engine study, please visit http://www.siteadvisor.com/studies/search_safety_dec2006.html