Have i been pwned ?

 haveibeenpwned

 

What is the site all about?

This site came about after what was, at the time, the largest ever single breach of customer accounts — Adobe. I often did post-breach analysis of user credentials and kept finding the same accounts exposed over and over again, often with the same passwords which then put the victims at further risk of their other accounts being compromised.

The FAQs page goes into a lot more detail, but all the data on this site comes from "breaches" where data is exposed to persons that should not have been able to view it.