In online social networks, social information, i.e., content generated and shared by users (e.g., past purchases), can be a substitute for sponsored advertising, which constitutes the network's main source of revenue. When will social information be let to spread freely over the platform? We...

We quantify the prevalence of undisclosed influencer posts on Twitter across a large set of brands based on a unique data set of over 100 million posts. We develop a novel method to detect undisclosed influencer posts and find that 96% of influencer posts are not disclosed as such. Despite...