Iran blocks 100,000 web sites
IT Analysis via The Register has a piece on internet censorship in Iran. It's a bit lacking in depth, but has a few details that are worth noting.
In order to implement the censorship, the mullahs send lists of the banned web sites - already more than 100,000 - to the 300 or so ISPs in Iran who are, in turn, obliged to prevent access to the sinful sites. There are problems with this. First, Iranian ISPs are not well equipped with the filtering software that they need to apply the dictates of the mullahs, and hence they get it wrong or do it slowly or both. Second, the web is organic, growing daily, so new 'degenerate' sites regularly emerge and also resurrections of banned sites spring up in new places. Third, the mullahs have no way of preventing seditious behaviour of any kind by email or in chat rooms. [...] Recently when there were popular protests in Tehran and other cities in Iran, the newspapers gave limited coverage of events. The student web sites became the only medium that reported the incidents in any detail. The mullahs have not yet tried to suppress these sites. Neither have they acted against some of the top portals, half of which either carry Iranian Internet porn or have web links that point to it. - IT Analysis, Blocking Internet Porn in Iran.