Research on vaccine criticism on the Internet is now at a crossroads, with an already important body of knowledge published on the subject but also a continuous and even growing interest in the scientific community. In this commentary, we reflect on the published literature from the standpoint of sociologists interested in social movements and their activists and the influence they can have on vaccination behaviors. We suggest several avenues of research for future studies of vaccine criticism on the Internet: 1) paying more attention to the actors who publish vaccine critical contents and to their use of the Internet in relationship to the other means through which they try to mobilize the population – the production of vaccine critical information on the Internet, and not only its nature and its reception, should therefore become one of the main objects of this strand of research -; 2) paying closer attention to what distinguishes the different strands of vaccine criticism regarding both what they dislike about vaccines (or about a given vaccine) and how this fight is integrated in a more general political or cultural struggle; 3) investigating further how the new forms of social interactions allowed by the Internet affect the transmission of vaccine related information and the capacity of vaccine critical actors to enroll members of the public in their political or cultural struggle.