I worked for a US company, as a software developper, that decided to block all the "shareware" "freeware" open source" and al websites, so we had no access to github, stack overflow, forums or anything interesting for developpers. We had to fight HR (it seems HR head had the decision to unblock site, try to explain what open source is...) to access them. It was a true nightmare, they were control freak of the web. The number of times you did a search, click on the answer you were looking for and bam! blocked!
We had bypass using different DNS or 3G on our phone, etc.