https://www.bleepingcomputer.com/news/technology/ghostery-tries-to-comply-with-gdpr-but-ends-up-violating-gdpr-in-the-process/

The company behind Ghostery, a privacy-focused browser and an ad-blocking browser extension,  has apologized for a technical error that occurred last Friday when its staff was sending out GDPR-themed notification emails.

According to numerous user reports, Ghostery sent out emails that exposed the addresses of other users.