In 2009 a well known company was hacked, they held their passwords in open text format and a hacker got inside, their password list was published and is widely used by hackers worldwide to formulate rainbow tables to hack databases. The text can be found here and one can simply open it in microsoft word and use the find function, if it’s on the list it’s probably worth changing and making sure your next one is much more secure.
Talking of password security there is a much better feature that makes you more resilient to what we call brute force attacks, this is where a computer just fires out random alphanumerical strings until it finds a solution. This useful tool is right here, and try to beat my score of six sextillion years!