You are going to be hacked whether you use social media or not. That’s just been a fact of life since the 1980s. There are plenty of software solutions for preventing hacking but social networking exposes the most vulnerable port to the hacker – the user. Social engineering is the primary tool of hackers because it works so well (ask Kevin Mitnick: The Art of Deception: Controlling the Human Element of Security).
The best way to handle the security issue is through user training. Here is one great example of fun and interactive social networking training – http://mashable.com/2009/12/16/telstra-social-media/