Last week we talked about giving away your passwords and how you should never do it.  When a website wants to use the services of another—such as Bitly posting to your Twitter stream—instead of asking you to share your password, they should use OAuth instead.OAuth is an authentication protocol that allows you to approve one application interacting with another on your behalf without giving away your password.This is a quick guide to illustrate, as simply as possible, how OAuth works.The ActorsThere are 3 main players in an OAuth transaction: the user, the consumer, and...