You can also creating similar service using Drupal, simply install a particular module, then your Drupal site can turn into a URL shortening services easily. Below are a few module you can use to creating your own URL shortener:
- Short URL This module is an API module that allows developers to create short URLs, this module only specialized to the developers.
- Shorten URLs Shorten URLs module provides an API to shortening URLs using almost any service (the default are 25 services).
- ShURLy This module wrote for Lullabot URL shortener: http://lb.cm.
Your own URL shortener is very important if you want keeping your brand in your tweets or status updates.