That login+password is a common crypto, used industry wide, and is easily deciphered.
Some nerds run the equivalent of a vacuum cleaner on the internet, sniffing out packets with these codes, and if they catch you while logging on, or checking your mail, the packet that contains your name and password can be picked up and run through a simple deciphering program to get your name and password.
A good idea is to have one password for things like chatrooms, and another for things like Paypal, etc...
I've spent some time doing secure web pages, and the basic rule to go by is, if the lock symbol on the bottom left of your browser screen is on, you are very secure, as you are running a very sophisticated cypher program. That's complicated crypto makes internet shopping, Paypal, etc... safe.
The one catch to this is, some viruses install themselves on your system and record keystrokes, emailing them out covertly later, in which case even the lock symbol does not help. To get around this, always run with virus protection.
If you are just logging into your dial up service, or checking your email from a web mail service, and the lock on the bottom is unlocked, you are broadcasting the simple cypher code.