Hootsuite (previously Ow.ly) is a URL shortening service that allows users to create a short URL and share it through email and social networks. It provides two options to shorten URL - anonymously or through Twitter. It also lets you upload images, videos and documents and share it through short URLs. These media can be shared through social sites and can be commented upon, rated and shared.
Bitly doesnt offer this service in their free plan. They consider it to be a premium feature and have made it available only to their paying customers.Another reason for this is to prevent spammers from abusing Bitly. "Bitly hasURL Shortening Tools Bitly