This tutorial will explain how to get a user's IP who is visiting your page.

There are many uses for IP Addresses in the internet world.  Some developers, especially of community driven sites, may use IP Addresses to block/ban malicious users.  I use IP to keep track of active users on this site.  These are just a couple reasons for tracking IP addresses on your page.

   // print the IP Address
   echo $_SERVER['REMOTE_ADDR'];
?>