Twitter recently announced that it would be using the t.co domain which it has acquired, to wrap each and every URL that users post through to it's service. By wrapping the URLs, Twitter is protecting users from harmful sites, giving them an insight into where the link will take them if they click on it.
Twitter offering a degree of transparency
It is said that URLs displayed on SMS devices will take the form of 'http://t.co/DRo0trj' whilst web users are likely to see a URL such as 'amazon.com/Delivering-' or, in some cases, the whole URL or page title as the anchor text. Obviously, in doing this, Twitter is looking out for it's users and is letting them know exactly where each URL is linking to.
The 'Promoted Tweets' platform will also benefit
There is a further reason for this change though. Not only is Twitter making this alteration due to security, but also, the company is developing a stronger system which will contribute to the metrics it gathers as part of the 'Promoted Tweets' advertising platform. It is said that the introduction of the t.co links will translate into an important quality signal for Twitter's resonance algorithm, and will be a deciding factor as to whether a tweet should be promoted. Of course there is also the potential for the company to use the data to create a comprehensive analytics suite which would be particularly interesting to the many commercial entities on Twitter.