: Validated accounts (called "hits") are then resold on marketplaces for a profit. How to Protect Yourself
Because these lists are "mixed," they are unpredictable. A user might have their credentials leaked from a small, forgotten forum ten years ago, but if that password matches their current primary email, they are at high risk.
: Generate unique, complex passwords for every single service so that one leak doesn't compromise your entire digital life.
A "mixed" combo list specifically implies that the credentials inside are not targeted at one specific site. Instead, they are a General Aggregation of logins from different sources across the web.