The increasing interest of citizens for websites, social networks, streaming services, and other online media has led to the web becoming an indispensable instrument in daily life for business activities, learning, entertainment, communication, etc. Internet users can now share and access a nearly unlimited amount of information. This opens up great opportunities to exploit this valuable information by transforming it into useful knowledge through appropriate techniques. In this context, data mining methods arise as efficient tools to help users in the recovery of suitable online information, products, or services as well as to explore a wide range social media aspects regarding user behavior, communities, networks structures, information diffusion, and many more.