One of the most useful tool in this day and age.
I find my self going to sites, just for pure distraction and that had a huge down impact on my work flow.

This plugin just solved the issue. When I realize that I'm on a site with no particular reason, I block it (youtube, facebook, etc.). If I really need them for some reason (not just wondering in), I can use them, but I have to put in extra effort pausing the block to do that and that's nice about this solution.

I only can recommend this plugin for those who suffer from distraction and procrastination like me.