The impact of consumer data on competition in online markets is gaining attention from competition agencies across the globe. Effective competition should theoretically drive better outcomes for consumers in terms of higher levels of privacy and control of personal data, but this is not always the case in practice, especially when consumers do not or cannot actively manage their privacy options. There are questions about whether the possession of consumer data raises barriers to entry and what remedies could best address such concerns, among others. This Going Digital Toolkit note discusses competition issues and identifies innovative ways that competition agencies are addressing related challenges. It also assesses some of the ways in which jurisdictions are improving co-operation between agencies with responsibilities across competition, privacy and data protection, and consumer policy and enforcement.