There are a handful of countries worldwide that implement Internet filters to limit what their citizens can see and do online. One of those countries is Iran, which is famous for defying the UN, and for producing images of non-existent war machines.
Now Iran is stepping up its level of filtering by blocking the use of most virtual private networks (VPNs) from civilian access, with only 'legal and registered VPNs' allowed through the firewall.
Until now, the use of VPNs has allowed many Iranians access to the world outside of the restrictions of that firewall, but for most those days are now over. This is believed to be part of an Iranian strategy to prevent Egypt-like events, where social media could be used to start mass protests or even a revolution within the country.
Apparently Iran's firewall now also blocks access to services such as Skype and Viber.
This is all in the lead-up to Iran's first election since 2009 - which led to large civil unrest throughout the country, the worst since the 1979 Islamic Revolution.
There are a number of other countries that also use various Internet filters, including China, North Korea, Belarus, Ethiopia, and more. Some western countries are also toying with the idea of filtering the Internet, including Australia - but not all have sinister objectives. For more information, see this article on Wikipedia.