Advertising disclosures would be on the ads themselves. If the app is gathering data and ads are generated from that data, the ad has the disclosure per Reg Z, DD, etc. and the app should (IMHO) indicate how the information may be used, some privacy info, and perhaps an opt-out. You're getting into legal EULA disclosures and the results may be one of those state laws are getting into where consumers have a right to see what is collected and where and to have data removed.
My opinions are not necessarily my employers.
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell