Shorten URLs will be used especially at Social Media sites to share web pages and interesting links. People are spending hours and hours in front of Facebook, Twitter etc, so URL Shortener services are increasing day by day. Most of people have this question that whether these short URLs are SEO friendly or not. Usually shorten URLs will redirect to destination URLs. We need to find out whether these redirections are permanent (301) or temporary (302). We have few free tools on the web to check it. Yes, URL Shorten Services are using permanent 301 redirection which is search engine friendly. Please have a look at the following screenshot and video for better understanding.
Mattcutts explaining the same in the following video:
