I wrote a bookmarklet to make up passwords for me. It asks for my master password, which is all I have to remember, and uses it to make a unique password for each site. It even types the password into any password fields on the current page for me, whether I’m registering for a new account or logging in on a subsequent visit. […]
How does it work? It gets the hostname from the page’s URL and mixes it together with your personal master password using a little cryptographic magic we call MD5. It will always get the same result if given that hostname and master password, but will never get that result if either changes. (Well, once in a few billion times it might.)
Just don’t lose sleep at night worrying about MD5 cracks.