Yellow background text boxes - Its Google Toolbar

I was really surprised to see in some registration pages that some of the text boxes having a yellow background color .I had come across that long time back too when I was designing some aspx pages with form input tags and today I really went into it to find out .
Google came up with Google Toolbar sometime back and they have an option of AutoFill.You can fill in all the basic information like Full Name , address ,City,State ,Zipcode etc , all the basic and common form fields that you usually see when you go for some site registration form.Google Toolbar collects the information (saves it in some secret place in your machine ... Will put some time to find out where) and next time you visit an ordering form / registration page , it will find out which all INPUT tags with id named as City ,State,Full name etc , It gived you an option of autofilling it by just clicking 'Auto Fill' in the Google Toolbar .It really helps you when you are a person who registers to all social media / networking websites or buy too many things from different online shopping websites.
To modify/edit some information you have already saved , Goto Settings (extreme right of the toolbar ) and modifying autofill text boxes.
Its really a cool option and I recommend all web developers to name the text boxes as it is (Like city, Name etc ) so that your visitors can make use of the cool option from Google Toolbar and perform registartion faster.