Reports from Reporters Without Borders (RSF):

Figures
At least 170 journalists and bloggers, including 32 women, have been arrested in the past year.
- 22 of them have sentenced to jail terms totalling 135 years.
85 journalists are awaiting trial or sentencing.
The amounts of bail that have been paid to obtain release total about 100 million euros (5.23 billion toman).
More than 100 journalists have been forced to flee the country.
23 newspapers have been shut down and thousands of web pages have been blocked.
With 37 journalists and bloggers currently held, Iran is one of the world’s four biggest prisons for the media, alongside Cuba, Eritrea and North Korea.

Undermining communications
Another of the regime’s responses to the protests against its historic election theft was to weaken the communication networks. The authorities cut the SMS network and slowed down the Internet two days before the presidential election. They systematically cut the mobile phone networks in the centre of the main cities whenever protests were held in June and July. The speed of Internet connections was also reined in.
The effectiveness of this procedure should not be overstated. It failed to prevent the marches and protests. During demonstrations, information about the date, hour and place of the next one was passed from person to person, as it was during the 1979 revolution.
Street newspapers and leaflets survived and continued to play a mobilising role during the summer and part of the autumn of 2009. The Internet and especially the social-networking website Twitter, of which so much was said during the summer of 2009 about its use as an opposition communication tool, played a key role internationally. But only 2 per cent of Iranians were able to use Twitter.
Read the whole report from the website of RSF:
http://en.rsf.org/iran-using-skilfully-devised-strategy-08-06-2010,37693.html