Besides hinting at new features and talking about user stats, Twitter also made a couple announcements this week. One is that all Twitter apps use OAuth . The other is that it will start tracking every t.co link users click. This is Twitter's own default URL-shortener. Twitter sent an email to users saying, "In the coming weeks, we will be expanding the roll-out of our link wrapping service t.co, which wraps links in Tweets with a new, simplified link... When this happens,