The Password Hasher is a Firefox extension that lets you create and remember complicated passwords easily.
The motivation comes from combining the need for strong passwords and the preference for easy-to-remember passwords. By hashing your simple password into a complicated one, you are able to secure your password since it’s difficult for hackers to guess. Yet you can use it with ease since you’re “generating” the actual password based on a simple keyphrase that you know.
I’ve not tried it myself so I do not know the actual benefits or quirks, but the idea is great. One of the first negative thoughts I have was is the hash based on a key? What if you lose the key, such as during a PC crash/reformat? You lose ALL your passwords?!