I’ve noticed since the update the twitter button in social-buttons-16px doesn’t format the link page as I’ve configured in wordpress. I have it configured as a permalink with the post name, but the twitter link just posts the post number.
Short URLs are used to increase the tweet text. Sometimes, the title will be longer and the long URLs will not have space. In order to avoid this, short URLs are used. Its a good idea only. Both these get to the same page only.