.... the response of Ayatollah Lotfollah Safi-Golpaygani, a senior cleric, to the question about Facebook and Iranian membership in the social networking service.
"Basically, going to any website which propagates immoralities and could weaken the religious belief is un-Islamic and not allowed, and membership in it is therefore haram (a sin)," the ayatollah replied.
"Only the use of websites propagating religious criteria and not leading to any kind of ethical immoralities is of no problem," he added.
.... Iranian officials have, for over three decades, been waging what they call a "battle against the invasion of Western culture."
This has led to blockades of "immoral" internet sites and banned Western music and movies. However, pirated versions of those are easily available on the black market. [Haaretz.com] Read more [via National Secular Society]
