Mohammad Hajarian is a Marie Curie Postdoctoral Fellow and a Professor at the University Carlos III of Madrid. He is a PI of an EU-funded project about developing engaging methods for regulating user behaviors in social media to prevent problems such as fake news, misinformation, online hostility, misogyny, and misunderstanding that can harm human mental and physical health. His research fields are Online Social Networks, Gamification, Human-computer Interaction, Interaction design, Recommendation Systems, Personalization, User Engagement, Data Science, and Online Marketing. He is also the programmer, designer, founder, and CEO of the Gegli social network since 2003 (Formerly known as Gohardasht.com), and he uses his social network to implement and investigate most of his algorithms and frameworks in a real environment. He also collaborates with other researchers to investigate their methods in a real social network environment. During his professional career, he participated in several software projects, conferences, and workshops and worked as a reviewer in several prestigious journals and conferences. Furthermore, he taught 35+ computer courses in several universities and supervised 10+ theses at the graduate and postgraduate levels. He published 50+ articles and books in computer science and software engineering. And his innovative contributions have been exploited in the social media industry.