I recently decided to make the switch to Ubuntu. And I had a question pertaining to site connections. Before beginning, I need to give some context. I am/was addicted to youtube. I think at my peak in my teen years I spent around 6 hours a day watching youtube. And so I decided to change that by making it impossible for my computer to connect to youtube.com. This was as simple as going into the windows 32 hosts files and plugging in the url of the site you don't want to connect to. It worked great and I've been much more productive.
I was curious if Linux Ubuntu had a similar functionality.