That has happened to me as well, when Dropbox leaked passwords (they claimed only emails leaked... bullshit). I reseted the Dropbox password right away, but som

That has happened to me as well, when Dropbox leaked passwords (they claimed only emails leaked... bullshit). I reseted the Dropbox password right away, but someone had access to my Steam account with the same password and purchased a game. I was able to get a refund, but my password probably got into some forum, every other week or so someone attempts to login into my Steam account (Steam now requires a token sent by email to login from a different computer). Lesson learned, never reuse passwords.