Effective interactions are essential for retail brands to progressively nudge consumers towards purchase. While social media provides the platform for brands to directly connect with consumers, it is critical that brands take privacy concerns seriously. This paper address common questions retailers ask: How do brands develop effective interactions with consumers on social media? Do consumer-brand interactions impact purchase intention? Does privacy matter? Through 541 UK participant responses and using social exchange theory, this research examines consumer-brand interactions on social media, focusing on how social media activities, attitudes towards social media advertising, and privacy, impact upon purchase intention. Our results show that brands must establish strong relationships through high-quality consumer-brand interactions to significantly raise purchase intentions, while also carefully managing consumers' privacy expectations. Effective privacy management positively mediates the link between social media and purchase intention but ignore privacy, and it becomes the Achilles heel of the relationship.