Those groups that have found advocacy success on Facebook tend to adopt an approach that USES the one-on-one nature of the site. As one small example, I spoke to a group of pro-choice activists a few weeks ago, many of whom work with students on college campuses. When I asked how Facebook fit into their work, the overwhelming response was that it was essentially an email replacement — they employed Facebook messages to reach individual supporters or small groups of supporters when they were preparing for events or promoting a particular message. The Genocide Intervention Network demonstrates a much more comprehensive and strategic approach but the same basic idea: as Ivan Boothe wrote last year.
Note that Ivan is describing something very different than traditional mass communications: he’s talking about working closely (no doubt frequently one-on-one) with people on Facebook and other networking sites over a long period of time to help build a cadre of very committed activists — something that most electoral campaigns (and even most issue advocacy campaigns) simply can’t do, whether because of lack of time or lack of resources.
Colin Delaney's article, "Has Facebook Jumped the Shark as a Political Tool?," references my article on organizing rather than mobilizing — that social networking is about communication, not finding another way to pump your supporters for donations or signatures on a petition. This might be particularly challenging for all but the largest and tech-savvy electoral campaigns (as Chris Hughes, now of my.BarackObama.com, would know). For extraparliamentary activism, though, it's still a powerful tool for meeting your supporters where they are and organizing them into long-term social movements.