firefox (and other) form vulnerability

Looks like there is a vulnerability in various browsers where you type data into one form but the data really gets sent to another window. An exploit to demo it is at Secunia's website and uses citibank as the form that you would fill in. It doesn't take a genius to work the potential of this exploit - however in this particular demonstration the keystrokes do not appear on the form so some people might get a bit suspicious, but then judging from the people who get infected by the latest virus's there are a lot of not very suspicious people out there in internet land.