The rapid development of e-Participation research in the last decade has resulted in fragmented, loosely related e-Participation models. In our previous work we established a comprehensive Integrative Framework combining existing models. In this paper we move further and conceptualize the elements strictly related to socio-technical aspects of e-Participation by constructing a formal ontology for e-Participation. The innovative model proposed addresses the duality of e-Participation by considering simultaneous government-led, top-down e- Participation, together with citizen-led, social media based e-Participation.