Group annotations on this page
a) We use this as confirmation that we typed what we meant to type.
b) It is a convention, it is what we expect and therefor get.
c) Web developers are bad habit forming idiots with preconceived ideas
d) if we type it twice we are more likely to remember it.
Instead of confirm password
One solution is to just kill that extra input, like Virb and Facebook have done. Another is to replace it with a “Show Password”-checkbox using the Show Password Jquery plugin.