The last 2 places I worked facebook and YouTube have been required for my job. One was working on firmware for a networking appliance, the other was an Internet security application. When a user calls in with a problem I need to be able to reproduce without jumping through some idiotic IT hoops, otherwise I'm wasting my time and the user's. Oh, and 1 of those companies was a company with over 100k employees, I very much doubt IT knew about every product the company created. Are you certain no one in your company, like maybe your social media manager, has a good reason to have open Internet access?