Many web sites have user I/D and password systems for our protection. Some of which in Fire Fox remembers as on here or E-bay. But on some, although FireFox did ask if I wanted it to remember- it does not come up with the goods, So i have to scrabble about in my password /registration folder- which is on an external HDD to find the one I want to copy/paste. All a bit of a palaver really So what do you do?
I always use the same username - which is alpha-numeric, and then I use a password system based on an easy-to-remember formula.
I use one password for all e-commerce sites, another for information sites, and a third for all other sites. Every month I change the passwords using a simple code. I never forget a password, once I know which month I'm in, and what type of site I'm on. Neither the username or the passwords are stored anywhere but in my head.
The key is simplicity - it's easy to come up with a system that has no recogniseable pattern, provided you think carefully about your convention before you start.
FE- Like you mostly it is really simple- providing it is a user/password one provides for oneself. However in the case that prompted the post the I/D is a long alphanumeric string that the site gave me. I should have mentioned that in the original post.