The document discusses private browsing modes and the threats they aim to mitigate. It outlines several use cases where private browsing could be useful, such as buying a gift for a partner or keeping employer/ISP from analyzing browsing traffic. However, it notes that private browsing does not fully address these threats and that other techniques like HTTPS, VPNs, blocking cookies and fingerprints may be needed. It hints that while private browsing aims to address user privacy concerns, there are limitations to what it can achieve.