A resurfaced instant message exchange from a 19-year-old Mark Zuckerberg has intensified the rivalry between Twitter and Meta Platforms Inc.'s Threads. The conversation reveals Zuckerberg's casual attitude towards user privacy in the early days of Facebook, raising fresh concerns over the company's privacy practices. The timing of the leak coincides with growing interest in Meta's Threads, and the impact on Facebook’s user base and public perception is yet to be seen.