I am surprised to see the careless implementation of OAUTH by almost all providers like Google, Facebook. I am pretty much sure that I might not be the only person who would have noticed it. By this time there could be atleast thousands of botnets which impersonate as a regular site and spam users' walls or create a social network graph as good as facebook. Probably there will be a separate Real Time Bidding auction by the impersonators. In short OAUTH+Javascript is like locking your door and leaving the key under your doormat. Lets discuss about the differences between the client based OAUTH flow and server based OAUTH flow As per Google's documentation , the server loads the page on client(browser) with the app id(public name). On initiating OAUTH with Google servers, the appid and redirection_uri is passed. The Google server calls the redirection_uri with a code. The app's server has to cross check the code with client_secret to get the access_token which has ...