Someone you don’t know has a new job. A company you couldn’t care less about is celebrating its 30th anniversary. A creative head at a production house—not in the least your business—is seeking “blessings” for a new project. A video sponsored by a large bank teaches you how to make a great resumé. All par for the course during a typical visit to LinkedIn, the world’s largest professional social network. With each passing day, LinkedIn is rapidly turning into a publishing platform, for both individuals and businesses, that can keep people engaged for increasingly longer.