Online platforms increasingly offer "paid" ad-free subscriptions as an alternative to the traditional "free" ad-based model. The transition to ad-free models ostensibly removes advertising as a key justification for data processing under the GDPR. So, normatively, platforms should collect less user data. However, platforms may justify continued data collection as a means to provide an improved, personalized experience. This tension between privacy principles and platform incentives raises a critical underexplored question: do data collection practices vary between ad-free and ad-based subscription models? In this paper, we shed light on this important privacy issue by investigating the alignment between platform data collection practices and related user expectations. With respect to data collection process, our analyses of data exports from three major online platforms - Instagram, Facebook, and X - reveal that these platforms continue to retain or collect some ad-related data, even in ad-free subscriptions. With respect to user expectations, our survey among 255 participants on Prolific reveals that 69% of the participants normatively expect data collection to be reduced, indicating their expectation of improved digital privacy in an ad-free model. However, when asked what they think actually happens, 63% of these participants believed that platforms would still collect about the same amount of data, highlighting skepticism about platform practices. Our findings not only indicate a significant disconnect between data practices and normative user expectations, but also raise serious questions about platform compliance with core GDPR principles, such as purpose limitation, data minimization, and transparency.

翻译：在线平台日益提供"付费"无广告订阅作为传统"免费"广告模式的替代方案。向无广告模式的转变表面上消除了《通用数据保护条例》下数据处理的关键理由——广告投放。因此，从规范角度而言，平台应收集更少的用户数据。然而，平台可能将持续的数据收集辩解为提供改进的个性化体验的手段。隐私原则与平台激励之间的这种张力引出了一个尚未被充分探讨的关键问题：无广告订阅模式与广告订阅模式之间的数据收集实践是否存在差异？本文通过调查平台数据收集实践与相关用户期望的一致性，揭示了这一重要的隐私问题。在数据收集过程方面，我们对三大在线平台——Instagram、Facebook和X——的数据导出分析表明，即使在无广告订阅中，这些平台仍继续保留或收集部分广告相关数据。在用户期望方面，我们在Prolific平台上对255名参与者的调查显示，69%的参与者从规范角度期望数据收集应减少，这表明他们期待无广告模式能带来更好的数字隐私。然而，当被问及他们认为实际情况如何时，63%的参与者认为平台仍会收集大致等量的数据，这凸显了用户对平台实践的怀疑态度。我们的研究结果不仅揭示了数据实践与规范性用户期望之间的显著脱节，更对平台是否遵守《通用数据保护条例》的核心原则（如目的限制、数据最小化和透明度）提出了严肃质疑。