There are security problems with this idea: 1. Your twitter password leaks information about your facebook password. E.g., "e" is encoded as "Rj" in both of th

There are security problems with this idea: 1. Your twitter password leaks information about your facebook password. E.g., "e" is encoded as "Rj" in both of them. 2. If attacker gets hold of your twitter generated password and assumes "twitter" is encrypted somewhere inside, he now knows how you encode "t", "w", "i", "e" and "r" in your other passwords. Numbers are easy to guess or brute-force. 3. It's too tempting to just add a number to password in order to change a generated password for some site. But the generated password barely changes (and remember that attacker could know how you encrypt numbers): Password: facebook Generates: 6F9xk6RjGVyp6yp6Hj8 Password: facebook1 Generates: 6F9xk6RjGVyp6yp6Hj8y