I've actually seen links on hackernews that go to these big data dumps of information. Presumably, you'd check to see if your info was leaked using the browser'

I've actually seen links on hackernews that go to these big data dumps of information. Presumably, you'd check to see if your info was leaked using the browser's find mechanism. A clever enhancement is that as you type, JS on the page actually inserts whatever you're typing into the content of the page. So you won't ever just type the first few characters of your password and see it's not there, you'll always find your info or similar info on the page. I agree that it does seem a touch unlikely to work in the real world. However, I think a scammer with a touch of ingenuity, creativity, and programming knowledge could probably construct a realistic enough scenario to fool many people.