We have our account on the plethora of web sites. Including mailing, banking, gaming, e-commerce, educational and what not. We do some kind of transaction and save sensitive informations in almost all of these accounts. It is recommended to not use same password on any two sites, but, by the sheer number of them, it feels kind of impossible for us to do so. Watch this video on "How should we manage our passwords in the most easy way"