Data and massive data collection increasingly define political and economic citizenship. Data infrastructure such as open data portals and data visualization platforms funnel citizen participation, capturing much of the contemporary imaginary of activists and ordinary users alike. The new forms information takes today—increasingly numerical and statistical—intervene to alter the ‘classical’ dynamics of citizen media, offering new opportunities but bringing about novel challenges, too. Meanwhile, new varieties of activism emerge in the fringes of the datafied society, such as data activism, civic tech activism, and freedom of information advocacy. This entry explores how and where non-commercial grassroots media and the related practices mee...