[youtube https://www.youtube.com/watch?v=V_tBr7MSoxQ&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&fs=1&w=425&h=344]

At the Web 2.0 conference in San Francisco last week, Facebook chief executive Mark Zuckerberg mentioned that Facebook is being used as an agent of political change around the world — a phenomenon he’s been talking about for years. And, as usual, the audience chuckled derisively. Sure, more hard data is needed to either support or refute his claim, but the anecdotes are mounting up in Zuckerberg’s favor.

In Saudi Arabia, a Facebook group was used to help organize and publicize a national hunger strike against the kingdom’s imprisonment of political opponents. In Egypt, young people used it to organize a nationwide work strike against the government’s totalitarianism — in fact, I first heard about this from Egyptians who had previously friended me on Facebook. Check out the 24-minute documentary, above, for more. The Egyptian government has even publicly named Facebook in propaganda, featuring citizens promising to never use Facebook again.

In Italy, young Italians have been surging on to Facebook in the last month or so, as Google Trends shows. Last week, autocratic Italian president Silvio Berlusconi made an off-color remark about Barack Obama — and Italian Facebook users responded by forming numerous protests against him and his comments. In a country where the internet is just coming into the national consciousness, this is basically unprecedented, writes Corinna di Gennaro of the Berkman Center for Internet & Society at Harvard University.

In the U.S., of course, Obama used Facebook to help build a following, especially among the site’s base of college students and 20-somethings. His official page has, as of today, 3,101,450 supporters (his MySpace page, incidentally, only has 902,633). Meanwhile, erstwhile Republican opponent John McCain has 614,500 Facebook supporters and primary opponent Hillary Clinton has 166,659 supporters. Obviously there were all sorts of factors at play here that influenced how many Facebook fans each politician has gained. Certainly, though, the Obama campaign’s decision to start using Facebook long before opponents — and hire a Facebook cofounder to help build out Obama’s own social network — played a part in his incredible traction on the site (and electoral win).

What’s special about Facebook, in particular? In contrast to other social networks, the site has always focused on getting real people to share real information and to use features like groups and events to organize real-world activities. This focus on the real world may account for its booming growth around the world — it now says it has more than 120 million monthly active users.

Given the tendency towards censorship in these and many other countries around the world where Facebook is growing, one has to wonder how long before the site starts getting blocked. Or worse, as contributor David Nordfors brought up last year, starts being forced by governments to hand over private, personal information about dissident users.