"A relatively simple ruse persuaded dozens of prominent security analysts to connect on their social networking Web pages with people who weren't friends at all. They were fake profiles, purportedly of other well-known security pros. The scam was designed to expose the trust that even some of the most skeptical Internet users display on some of the most insecure sites on the Web. Some social networking sites can be dangerous because they allow people to post programming code — used for good or evil — on other people's pages. Even networking sites that don't allow that step carry their own security risks, because it's relatively easy for someone to masquerade as a "friend" who isn't actually friendly — and recommend malicious websites to click on."
Read more of this news article in "Even computer security pros vulnerable to scams", USA Today, August 8, 2008.