In this tutorial, we will develop an ASP.NET application to track users from Facebook, Twitter, Dzone, etc., who visit out website. Application consists of an HTTP module and a custom web server control. We can identify these users during this and subsequent visits using cookies. We can use this application to display to these users 'like', retweet and voting buttons to increase the reach of our content in social networks and bookmarking websites. The author displays live working example of this application on his website that displays Dzone voting button only to Dzone users and visitors. The code is free, fully explained and available for download.