Mozilla is looking at how it can alert users of a data breach when visiting a site that has been breached:

Firefox operator Mozilla is looking at adding a feature into the browser that would alert users if their credentials have been involved in a data breach, by integrating with Troy Hunt’s haveibeenpwned.com breach database.

Its functionality at the moment – the tool is currently being prototyped – involves a notification bar that appears to users when they visit a site registered in haveibeenpwned.com as having been breached.

Nice move. Not what I had in mind yesterday, but a good step in the right direction.