The internet gets blamed for a lot of things, our current crisis of criticism being just one of its victims. The explosion of free content, the rise of unpaid bloggers, a diffuse democracy of likes and retweets, has surely weakened the authority of traditional critics. But in this new landscape Mimi Zeiger sees a host of new possibilities for architectural debate. Explaining her notion of ‘collective criticism’, she shows how platforms like Twitter can help build momentum on critical issues that often fall through the cracks of the pressroom floor.