This is correct. Once clients adopt it (we do, at Twitterfall), this will in some ways improve how informative URLs are, as each tweet object will contain the actual URL the t.co link points to in the metadata, allowing clients to display that, essentially overcoming the 140 char limit.
Of course, you are free to use your own ahortnener; the t.co link will redirect to shortened links too (adding another layer of redirection is a bit of a pain though)
Of course, you are free to use your own ahortnener; the t.co link will redirect to shortened links too (adding another layer of redirection is a bit of a pain though)