Does your workplace allow tweeting? Or has your boss blocked access to Twitter, Facebook, and the other social networks thought to utterly decimate worker productivity?

This infographic from Socialcast takes a look at the state of social media access policies at various workplaces, and how that impacts employee productivity.

According to the 1,400 US chief information officers interviewed for this infographic, only 10 percent of US companies allow unlimited social networking while at work. 19 percent allow access for business purposes only, while 54 percent of respondents said their firms do no allow employees to use social networks for any reason while at work.

However, the infographic points out an interesting contradiction between what these workplaces believe about social media and the impact that social media actually has on their employees.

According to a University of Melbourne study cited in the infographic, those employees who engage in “workplace internet leisure browsing” such as watching videos and keeping up to date with friends while at work at 9 percent more productive than those who don’t.

There are a few other interesting takeaways from this infographic, including how Europe is doing social networks in the workplace differently. Check it out below (click to enlarge):