The lecture by our former member Tiago Santos, TU Graz will take place at the Complexity Science Hub Vienna.
Why and how some Question & Answer (Q&A) communities gain traction and attract activity from large numbers of users—while others do not—are questions of theoretical and practical relevance. Understanding how users become active in such systems, and how user activity evolves over time, can be considered an important stepping stone towards better modeling and shaping of online Q&A communities. In this talk, I present our recent work that quantifies the impact of self- and cross-excitation on the temporal development of user activity in Stack Exchange.
We study differences in user excitation between growing and declining Stack Exchange communities, and between those dedicated to STEM and humanities topics by leveraging Hawkes processes. We empirically show that a range of excitation effects distinguishes communities defined by different levels of success and different topics, we validate the statistical significance of our findings, and we quantify the impact of these excitation effects with a range of prediction experiments. Our work enables researchers to quantitatively assess the evolution and activity potential of Q&A communities.
Tiago Santos received the MSc degree in computer science from the Graz University of Technology in 2016. He is currently pursuing a PhD in computer science also at the Graz University of Technology, where his research focuses on online knowledge communities, event stream mining and time series analysis and where he also teaches introductory computer science and data mining courses.