How can open blocked sites?

Perhaps this question is more a question among the many Web users to block the view of many of the sites for work in many countries.
For example, in the United States is blocking a number of major sites and that unpopular very large, around the world.
For example, site Facebook is blocked in many countries in America and Canada.
YouTube is also blocked and a lot of other sites.
After now would not be blocked any of these sites, and we will ask more of proxy sites to overcome the blocking.