Ok, let’s face it. Blocking a website will never effective to gain any desired result. There were too many ways to re-open those blocked website. You could use VPN, Proxy, DNS Jumper, or even Tor (with all consequences off course).
There are lot of VPN provider in this world. Simply put, you connect to those VPNs to gain access to any blocked content that has been set up in your company, institution, or maybe even your own government. Some VPN give you enough encryption to make your traffic somewhat more secure.
Not quite effective now. Almost all public proxy has suffered degraded service. This is the simplest way and maybe because of that simple nature (just set your proxy settings on your browser) has made this method as the first choice to unblock the content. Secure wise, any traffic to those proxy often not encrypted. It’s simple, but not that useful anymore.
This method is useful when your internet provider has blocked the content based on their DNS. To make it short, DNS is a system that convert domain name to its respectable IP address. Internet provider often use this method to “redirect” that conversion so for example, if a.com has original address of 18.104.22.168, ISP DNS will change that conversion to 22.214.171.124 in order to block its content. DNS Jumper will prevent this by making all request to DNS port (default: TCP/UDP 53) to another independent server, get their result, and give it result back to you (or your browser). A little bit more complicated way will involve you to provide your own router and DNS server. But this is the most effective way to unblock blocked content when your ISP use DNS blocking method.
With all “workarounds” like that, is it still efficient to block any website? I don’t think so.