Alas, this section got cut from the conclusion of "Web of Influence":

Authoritarian states that seek to censor the Internet can easily censor blogs. Ironically, blogs are nearly as easy to block as to create. Governments can stymie their citizens’ access to a large fraction of the blogosphere by filtering out standardized blog URLs such as Blogger or Typepad. China has on occasion blocked all blogs based at blogger.com, blogs.com, and typepad.com... wherever Internet content is restricted, so are bloggers.

Unfortunately, as my co-author Henry Farrell points out, this point can now be seen in Iran. Nazila Fathi reported on it yesterday in the New York Times:

Iran has continued its crackdown on journalists, with two arrests in the past week, and has moved against pro-democracy Web sites, blocking hundreds of sites in recent months and making several arrests....

As part of its crackdown, the government has blocked hundreds of political sites and Web logs. Three major pro-democracy Web sites that support President Mohammad Khatami were blocked in August.

A university in Orumieh in northwestern Iran shut down its Internet lab, contending that students had repeatedly browsed on indecent Web sites.

The crackdown suggests that hard-liners are determined to curtail freedom in cyberspace. Many rights advocates had turned to the Internet after the judiciary shut down more than 100 pro-democracy newspapers and journals in recent years.

The number of Internet users in Iran has soared in the last four years, to 4.8 million from 250,000. As many as 100,000 Web logs operate, and some of them are political.

The move to block Web sites has the support of a senior cleric, Ayatollah Makarem Shirazi, who declared in September in the hard-line daily newspaper Kayhan that Web sites should be blocked if they "insult sacred concepts of Islam, the Prophet and Imams," or "publish harmful and deviated beliefs to promote atheism or promote sinister books."

Jeff Jarvis argues that, "They [the mullahs] will fail. This can't be stopped now."

For reasons laid out here (see p. 488-490) and here, I am more pessimistic.

UPDATE: For some more background on this crackdown, which has been going on for the past few months, check out this Hossein Derakhshan post from two months ago (link via Rebecca MacKinnon) as well as this Human Rights Watch press release from last month.