In the past few days, Mahmoud Ahmadinejad's Islamist government has blocked access to several major international websites, and demanded that all Iran-based Internet sites are officially registered with the country's Culture Ministry.
Sites such as YouTube, Wikipedia and Amazon were all blocked in the recent crackdown, indicating that Tehran is now casting its censoring net wider in a bid to protect citizens from what it sees as corrupting influences.
According to the human rights group Reporters without Borders, "The government is trying to create a digital border to stop culture and news coming from abroad - a vision of the Net which is worrying for the country's future." The group lists Iran among its 13 "enemies of the Internet."
Julien Pain, the Internet Freedom Editor for Reporters Without Borders, believes the ban of sites like Wikepedia and YouTube are particularly significant examples of culture-blocking.
"They want to block access to other cultures, especially the West; that's why they want to prevent people downloading videos and music."
Pain also sees a worrying trend -- that Iran is copying China, the world's most stringent enforcer of Internet regulations.
"A regulation introduced in China is then followed a few months later in Iran. China is acting as a model," Pain says.
Iran shares China's record of mistreating bloggers and so-called cyber-dissidents and has the dubious distinction of being the first ever country to jail a blogger. In 2003, the Iranian dissident Sina Motallebi was imprisoned for apparently insulting Iran's supreme leader in his blog.
But according to Pain, there are significant differences between Iran and China's approach to cyber-censorship.
In October, the Iranian government banned all high-speed Internet access (above 128 kilobits a second). At the time, Iranian officials told the Guardian newspaper the step was taken to prevent the "undermining [of] Islamic culture among the younger generation".
Pain believes that China would never take such a drastic step as it is not economically viable.
"It's not a wise decision [for Iran to ban broadband] as it will hinder their economic development."
The Chinese government would not risk losing valuable business opportunities by banning broadband, but the Internet censors in Iran have a much more irrational, haphazard approach in contrast to China's regimented and pragmatic one, observers say.
The board of censors (or those responsible for filtering, as they prefer to be called) in Iran is not totally centralized; it's made up of members from several different ministries and governmental departments that do not always agree on what should or should not be filtered. Sites that cannot be accessed one day are often swiftly reinstated, only to be blocked again, a few days later.
Internet users in Iran are so used to being greeted with messages saying "this site is forbidden" or "this page has been filtered" that they are finding ways to circumvent the government's restrictions.
"We're all becoming hackers, finding ways to get round this" says Afshin Abtahi, ABC News' fixer in Tehran.
"You call your friend and they'll give you an IP address to get round the filters. People are basically trading in IP addresses."
Software and technology such as those discussed on www.sourceforge.net and www.linux.com are enabling people to disguise their computers' IP addresses and access sites as if they are not in Iran.