what are the differences between t.co and goo.gl and bit.ly ?

Links shared on Twitter.com will automatically be shortened to a http://t.co link.


The link service at http://t.co is only used on links posted on Twitter.com and is not available as a general shortening service on other apps or sites.

URLs converted by Twitter’s link service are checked against a list of potentially dangerous sites, and when there’s a match, users will be warned before they continue.

But where as bit.ly and goo.gl can use anywhere.