According to news published in English  and Persian  on July 25, the Wikipedia free encyclopedia website was blocked in Iran and could not be accessed. Users tryng to acess the website are having this blockpage  stating “By refering to the law concerning computer related misdeeds (crimes) access to this site is not available.”
An investigation I conducted  shows that on the morning of July 29th, the website Wikipedia was available  within Iran, but the reported Persian website  (balatarin.com) is blocked  in Iran. This blockage of Balatarin is due to its position  against the government and its “crucial role in the pro-democracy movement in Iran“, as it explains in its About page . As well as “many of the human rights abuses were publicized on Balatarin for the first time”. For this reason “Iranian government has in numerous occasions blamed Balatarin along with Facebook and Twitter as the “plotters” of the after election turmoil in Iran.”
We mention the example of Balatarin here as a testimony to the phenomenon that exists in Iran for for many years: websites that are blocked permanently in the country, while others are blocked from time to time due to specific causes.
In addition, the Iranian authorities had coped with the situation of differences in Internet filtering policies. This is due to the existence of many Internet ISPs which fulfilled the government's policy in different ways. Which creates a situation in which sites are blocked in one region but available in another area. To prevent this problem, the Iranian government worked  several years ago to create a comprehensive system, based on an Iranian software company, with the aim to create one unified filtering system that enables to deal with various different circumvention technologies.