Recent analytics studies have shown that Twitter is being unfairly prejudiced in most reports. After all, the 140 character limit on Twitter means that if you want to share a link on Twitter, you often can’t fit it. Hence the evolution of bit.ly and other link shortening services. But here’s the problem. These referral services often take Twitter’s credit as the referral.
For instance, let’s say you share a bit.ly link on Twitter that links to your site. If you look at your site’s referring traffic, Twitter doesn’t get credit for the referral. Bit.ly does.
Perhaps because of this, Twitter has released their own Analytics API, hoping to help Webmasters understand the importance of the growing social media juggernaut. In essence, Twitter is adding their own t.co URL to any third-party URL shortener to ensure they get credit for the referral.