Just off the heels of a report that 45% of employers now screen social media profiles during the hiring process is more research on corporate social media behavior.

It turns out that more and more companies are doing more than just screening - they're also actively blocking employee access to social networking sites.

According to ScanSafe, a web security software provider, there has been a 20% increase in the number of companies blocking social networking sites — ie. Facebook and Twitter — in the past six months. That research is based on more than a billion of the processed web requests that the company receives each month.

ScanSafe's research found that, "Currently, 76% of companies are choosing to block social networking and it is now a more popular category to block than online shopping (52%), weapons (75%), alcohol (64%), sports (51%) and Webmail (58%). Surprisingly, employers don’t take the same stern approach to online banking and less than half (47%) of our customers block this category."

It's quite possible that the rise of malicious activities, like Facebook and Twitter phishing and spam attacks, are frightening employers who may fear security breaches. Plus, there's always the age-old concern that allowing access to social media sites decreases workforce productivity.

Whatever the reason, it appears that even though many big brands and small businesses alike are seeing social media success, there's still plenty of fear to go around when it comes to employers and social networking sites.

Image courtesy of iStockphoto, alexsl