Dropbox - Password strength is indicated by colored bars underneath the input field. /via rammionline
From xkcd and Lifehacker: How to create passwords that are both easy for you to remember and hard for computers to hack
Password-Strength is a jQuery based password strength checker and indicator that helps users meet your minimum password requirements.
How to Craft Effective Registration
Beanstalk - The password strength indicator shows you the amount of hours needed to crack it.
8 Best jQuery Password/Strength Meter Plugins | SmashingApps.com
How Your Passwords Are Stored on the Internet (and When Your Password Strength Doesn't Matter) -- LifeHacker, June 20, 2012
Разрабатываем привлекательный измеритель безопасности пароля
GoCardless Password Strength-O-Meter (gif)
PassStrength is a jQuery password strength validation plugin to keep your passwords strong and a visual representation of password strength.