We’re not very happy about this one. LinkedIn and Twitter have worked together since 2008.
From the LinkedIn Blog:
As Twitter shared earlier today in a blog post from Michael Sippey, they are increasingly focused on “providing the core Twitter consumption experience through a consistent set of products and tools.” Consistent with Twitter’s evolving platform efforts, Tweets will no longer be displayed on LinkedIn starting later today. We know many of you value Twitter as an additional way to broadcast professional content beyond your LinkedIn connections. Moving forward, you will still be able to share your updates with your Twitter audience by posting them on LinkedIn.
Read the Complete Post
Explains that if you initiate you 140 or less tweet on LinkedIn first, it can (if selected) auto post on Twitter.