This lecture seeks to contribute to the study of authenticity and influence on the internet by exploring a series of techniques for the examination of online spaces where actors and information are either difficult to authenticate and verify or are known to verification specialists and fact checkers as problematic. Such online realms we refer to as post-truth spaces, which references the rise of the discourse of ‘alternative facts’, especially as part of a counter-program for ‘asserting political dominance’ and influence. The contribution is methodological as well as conceptual. In the technique I locate and discuss clutches of actors and websites as well as social media posts grouped together on the basis of their dense inter-referencing and their verification assessment based on digital investigation techniques. Their influence is gauged by the extent to which they penetrate or overlap onto mainstream spaces online. Conceptually, the post-truth space is among other spaces where ‘problematic information’ holds sway and information circulation, campaigning and operations are undertaken. Among these are the ‘alternative influence network’, ‘fake news’ engagement spaces, coordinated inauthentic behaviour campaigns as well as participatory propaganda circulation. As with a post-truth space, which as I discuss is a broader term, each of these is mapped through techniques that demarcate, chart or otherwise render them as spaces of interest online.