A model of an ad-financed platform is proposed in which platform profit, consumer surplus, and user participation depend on the platform's choice of data collection intensity. The equilibrium is governed by two key parameters: data squeezing, which captures the platform's effectiveness in turning users' personal data into commercial revenue, and privacy concern, which describes the distribution of users' sensitivity to privacy loss. Data extraction is characterized across alternative business models (Pure Advertising, Pure Subscription, and Freemium), and the platform's endogenous response to a tax on digital advertising revenue is analyzed. Endogenous business-model adjustment can fundamentally alter the effects of policy: Freemium induces more intensive data extraction, raises the tax required to trigger a switch to Pure Subscription, and, below that threshold, reverses the effect of taxation on data collection—higher taxes increase rather than reduce data extraction. Important interactions between taxation and privacy regulation are also identified, along with welfare benchmarks for alternative policy interventions.