One rather annoying and stupid thing I have seen on some web sites are forms where they ask you to enter your email address twice. For some reason the people who created the site seem to think that having your browser insert the same value in two fields is somehow better than having your browser insert the value once. It isn't like your browser is going to make a typo and enter something different in each of the fields.
These pages have been created by people who don't know how browsers work since as mentioned their visitor can if they want to have their browser memorise and fill out their email address for them. If someone doesn't get their browser to memorise their email address then that is their choice and forcing them to enter their email address twice isn't going to change the way that person uses their email address.
Three of the five most popular browsers will remember your actual email address for you and will fill it out automatically in forms with at most you needing to type the first letter and select your email address from the list of entries that display.
The other two popular browsers don't have a specific option for remembering your email address but do have an auto complete option where once you have entered your email address in one form you can then enter it into subsequent forms by simply typing the first few letters. You just need to make sure that you have auto complete turned on in these browsers.
So that's three of the top five browsers can fill in your email address for you with a single mouse click and two that will fill it in by typing the first few letters. None of the five most popular browsers will allow you to accidentally mistype your email address after you have the browser properly configured to remember it. So why do web pages insist on the browser filling out two fields with that same value?
This article written by Stephen Chapman, Felgall Pty Ltd.