In Google's Safe Browsing rating system, the company has rated its own google.com domain as "partially dangerous." According to an archived Copy of the listing, the reasons for the rating are (hyperlinks removed):

--Some pages on this website install malware on visitors' computers.
--Attackers on this site might try to trick you to download software or steal your information (for example passwords, messages, or credit card information).
--Some pages on this website redirect visitors to dangerous websites that install malware on visitors' computers, including: 7b726aeb-a-62cb3a1a-s-sites.googlegroups.com, polnu4ewtan4iwki.ws, and 40d0dfd9-a-62cb3a1a-s-sites.googlegroups.com.
--Dangerous websites have been sending visitors to this website, including: maeaflordapele.com, valeimaginar.blogspot.com, and bou7out.blogspot.com.

My comment: Give Google a badge for honesty, lol.