Social media has transformed online marketing from a one-way promotional activity into an interactive relationship between brands and consumers. Recent studies indicate that interactivity, electronic word-of-mouth, and engagement-based participation are strongly associated with purchase intention in digital environments. This paper synthesizes current evidence on how social media influence shapes consumer attention, trust, engagement, and buying behavior in online marketing. The discussion also highlights practical implications for marketers, educators, and researchers who seek ethical and effective digital strategies.