A co-worker of mine was telling me that she clicked a main link, not an advertisement link, for a search she'd been doing on Google and it redirected her to another site and downloaded a virus to her computer. McAfee did NOT recognize it as a virus but as a program is what the computer expert told her. He also said that the Search Engine companies have been targeted with this virus and that you should type the link address into your address bar and NOT click the link. The link redirects you to the virus site.
Normally, I would Google for the information but that's kind of defeating the purpose, don't you think?