OAuth allows you to share your private online resources (photos, videos, contact list, bank accounts etc..) stored on one site with another site without having to hand out your username and password. There are many reasons why you should not share your private credentials. Giving your email account password to a social network site so they can look up your friends is the same thing as going to dinner and giving your ATM card and PIN code to the waiter when it’s time to pay. Any restaurant asking for your PIN code will go out of business, but when it comes to the web, users put themselves at risk sharing the same private information. OAuth to the rescue.

More information about OAuth can be found here I will be looking at OAuth in relation to connecting to twitter to access user details in the future.

Check out the Example below to see the end user experience.