In an age where digital traces permeate every sphere of social life, research practices increasingly rely on data that are neither elicited nor designed but spontaneously produced through interactions within socio-technical systems. These innovations open unprecedented opportunities for social inquiry while simultaneously exposing researchers to new epistemic and ethical uncertainties. The abundance of digital information challenges conventional approaches to sampling, validity, and interpretation, as the availability of data often precedes theoretical formulation and drives methodological choices. This new digital environment blurs the boundaries between what is public and private, accessible and legitimate, raising questions of privacy, consent, and responsibility that existing ethical frameworks struggle to address. At the same time, algorithmic mechanisms, platform logics, and self-presentation strategies generate subtle yet pervasive forms of bias that reshape the trustworthiness and representativeness of research outcomes. Bringing together diverse theoretical reflections and empirical case studies, this volume explores the complex interplay between methodological innovation and ethical responsibility in digital social research. It aims to provide scholars and practitioners with critical insights into the dilemmas, biases, and promises of conducting research in a world increasingly mediated by data and algorithms.