Online misinformation, and particularly “disinformation” (deliberate misinformation), is rampant around the world, and has polarized political discourse within nations. It has also been used to manipulate election campaigns and sway public opinion on controversial social issues. Social media and messaging service WhatsApp has been at the center of such disinformation campaigns in developing nations like India and Brazil. This paper analyses and contrasts the use of three different social media platforms - Twitter, Facebook  and WhatsApp - in disinformation, through the Actor-Network Theory (ANT) framework. ANT is a framework to describe socio-technical paradigms through a network of “actors”. Through classical methods defined within ANT, this paper describes a model for “unblackboxing” the socio-technical paradigms created by each of the three platforms that have enabled online disinformation. Through this “unblackboxing”, the paper identifies the key differences in the amenability and utilization of each of the three platforms for disinformation. The paper finally examines how these differences have led to WhatsApp emerging as a preferred platform for disinformation in developing nations.