Beyond the realm of official politics, in which public discussion has tended to be institutionally shaped and managed, there is a vast sphere of autonomous interaction, taking place within and between publics and counter-publics. In this public sphere people encounter one another intentionally as well as accidentally, purposefully as well as promiscuously, rationally as well as affectively. Such encounters are increasingly taking place online, and, although the Internet might not qualify as a public sphere in the Habermasian sense, it does provide particular opportunities for citizens to interact beyond, around and across institutionally-controlled communication channels.

By reducing the costs of finding, contacting and maintaining communication links with others, the Internet has made it much easier for dispersed groups of people to form associations, share knowledge and mobilise for political action. Lowered barriers to collective action have benefited a range of citizen-activists, including protesters against corrupt and dictatorial regimes (Cleaver 1998; Chase and Mulvenon 2002; Teitelbaum 2002; Graham and Khosravi 2002; Zittrain and Edelman 2003; Semetko and Krasnoboka 2003; Wheeler 2005; Kalathil and Boas 2006; Soon and Kluver 2007), traditionally marginalised, excluded or stigmatised communities (Goggin and Newell 2003; Skelton and Valentine 2003; O'Riordan 2005), transnational social movements (Diani 2000; Bohman 2004; Tarrow 2005), electoral underdogs (Gold 2002; Gibson, Ward and Nixon 2003; Wolf 2004; Trippi 2004) and alternative media producers (Meikle 2002; Downing 2003; Platon and Deuze 2003; Couldry and Curran 2003; Kahn and Kellner 2004; Haas 2005; Pickard 2006; Bruns 2006).