Disqus, a comment hosting platform embedded across major news sites, blogs, and digital media properties worldwide, suffered a data breach in July 2012 that went undetected for over five years. The intrusion was not discovered until October 2017, when the stolen data surfaced. The breach affected approximately 27.8 million user accounts. The attack vector was not publicly identified. The exposed data included email addresses, usernames, and passwords stored as salted SHA-1 hashes. SHA-1 is an older hashing algorithm that, while better than storing passwords in plain text, is now considered weak and crackable with modern tools. Users who had logged in through social accounts such as Google or Facebook had no stored password exposed, but their account references were included. Because Disqus operates across thousands of third-party sites, the breach also exposes a risk specific to the platform: commenting history tied to a single Disqus identity can be used to correlate pseudonymous usernames with personal views, political opinions, or other identifying information across sites. No regulatory action or legal settlement specific to this breach has been publicly documented. Once the breach was discovered in 2017, Disqus disclosed the incident promptly and notified affected users, prompting password resets. People affected by this breach should treat any reused passwords as compromised, particularly if those credentials were used on other sites. The five-year gap between the intrusion and its discovery means exposed data had ample time to circulate before users had any opportunity to act.

Commenting and engagement platforms collect user accounts, emails, usernames, passwords, IP addresses, and public discussion history across large networks of websites.

Disqus continues to operate under Zeta Global's ownership as part of its marketing technology portfolio. The comment platform market has contracted as major publishers have disabled reader comments or moved to social media-based discussion. Disqus has maintained its presence among publishers that still host reader comments but its cultural prominence has diminished.