In today's world, digital technologies are increasingly mediated by artificial intelligence systems whose inner workings are complex and often opaque, raising important questions about their societal impact. Our group brings together strong computational and engineering expertise to study the safety and integrity of online ecosystems. Our work combines scalable computational methods with causal experimental designs to audit algorithmic systems, assess the safety of information exposure across digital platforms, and evaluate the risks posed by large language models—from adversarial vulnerabilities to persuasive capabilities. By studying the complex interactions between algorithms and human behavior, we aim to understand how digital technologies shape information exposure, public discourse, and societal outcomes.