Medley: Predicting Social Trust in Time-Varying Online Social Networks

Social media, such as Reddit, has become a norm in our daily lives, where users routinely express their attitude using upvotes (likes) or downvotes. These social interactions may encourage users to interact frequently and form strong ties of trust between one another. It is therefore important to predict social trust from these interactions, as they facilitate routine features in social media, such as online recommendation and advertising.

Conventional methods for predicting social trust often accept static graphs as input, oblivious of the fact that social interactions are time-dependent. In this work, we propose Medley, to explicitly model users' time-varying latent factors and to predict social trust that varies over time. We propose to use functional time encoding to capture continuous-time features and employ attention mechanisms to assign higher importance weights to social interactions that are more recent. By incorporating topological structures that evolve over time, our framework can infer pairwise social trust based on past interactions. Our experiments on benchmarking datasets show that Medley is able to utilize time-varying interactions effectively for predicting social trust, and achieves an accuracy that is up to 26% higher over its alternatives.