Social networking

Facebook, Myspace, Twitter and other programs are widely used even when you're at work. Email security has improved so hackers interests have moved towards the social networking sites.

There is a possibility that someone at work is using one of the above mentioned programs and gets infected or lets someone in into the company's network by accident OR intentionally..

Quote from the attached PDF:

NOTABLE INCIDENTS IN Q1 2009
The online identities of several high-profile celebrities were hacked, including the Twitter accounts of Barak Obama, Britney Spears and the rapper, Kanye West. Two incidents caused particular harm to the violated celebrity. In one, a hacker broke into Twitter, stole a celebrity’s password and used the same password to log on to the celebrity’s Gmail account. The hacker then found and published embarrassing pictures of teen star Miley Cyrus. In the other incident, a hacker broke into female rapper Lil Kim’s MySpace account and used the access to besmirch a colleague.

In at least two incidents, false rumors were spread about Apple CEO, Steve Jobs’ health, causing Apple’s stock to plummet. In one of the incidents, an abused user contributed images to Wired.com, while in the other, someone broke into a live Mac Rumors feed to announce Job’s death.

Lastly, multiple vulnerabilities have hit Twitter, causing false tweets to be sent by hundreds of famous people, and user contact information to leak, thus potentially exposing Twitter users to malware. These incidents have made Twitter acutely aware of its responsibility to address the security needs of its customer base.