Themes are programs that you can buy and install onto a mobile device.  When in use the them will give the user interface a new look.  It can change the background, Clocks, colors, and even the icons used on the phone. 

Many people like using themes because themes allow for personalization that they can’t get with just a wallpaper.  Also the can make using your phone easier. By eliminating complicated backgrounds that prevent easy reading of messages.