Most social networking and Web 2.0 sites have been victims of malware at some point or another and LinkedIn is no different. The latest threat relates to many phony profile pages which tempt users with pictures of nude celebrities. When the user clicks on one of the links, they are taken to an external site which attempts to launch an iFrame browser exploit and then redirects the user to other potentially harmful sites.
Earlier this week, Twitter itself was the victim of both a large phishing attack as well as the hacking an defacing of an number of celebrity accounts.
Moral of the story, think carefully about clicking on those links.