What are “pastes” and what do they have to do with data breaches?

Often when online services are compromised, the first signs of it appear on “paste” sites like Pastebin. Attackers frequently publish either samples or complete dumps of compromised data on these services. Monitoring and reporting on the presence of email addresses on the likes of Pastebin can give impacted users a head start on mitigating the potential fallout from a breach.

When you search for an email address on this site, both known data breaches and pastes are searched simultaneously. After the results are returned, they both appear side by side with an indication of where the address was found in a breach versus in a paste.