How to use t.co ?

Type or paste a URL into the Tweet box on Twitter.com.

    As you begin entering a URL, a message will appear at the bottom of the Tweet box letting you know that the link will appear shortened.

Any length of URL will be altered to 19 characters. Your character count will reflect this.
    Click "Tweet" to post your message and URL.

    Once a Tweet is posted, URLs will be assigned a t.co link ID but may appear as a shortened version of the original URL as shown below. Again, you cannot opt out of link shortening on Twitter.