Bitly is a URL shortening service that offers URL redirection with real-time link tracking. It is available through its website, browser extensions, mobile web, and third-party tools integrated with its open API. URLs that are shortened with the bitly service use the bit.ly domain. It also offers user owned custom domains to generate shortened links in its enterprise solution. The analytics can be segmented by department, location, channel, brand or user for measure of content being shared. Its reporting also gives you stats about social engagement and allow you to take ownership of your brand across marketing channels. You can also customize the back half of your branded Bitlinks to drive CTR. Bitly also plans to add features like retargeting, audience syndication, predictive modeling and cross-channel engagement in future.
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