BlueTicks collects the minimum data needed to provide read receipts: the Gmail address of the account you enable, and, for each tracked email you send, technical identifiers (tracking ID, Gmail thread/message IDs) and open timestamps. No message content, subject lines or recipient addresses are collected — those stay in your browser. No IP addresses are stored, no browsing history, no profiling, no advertising. Data is never sold or shared with third parties. Full policy: https://blueticks.io/privacy/