If LinkedIn want greater engagement, they need to start offering professional functionality that is useful on a day to day basis. LinkedIn Answers is okay, but

If LinkedIn want greater engagement, they need to start offering professional functionality that is useful on a day to day basis. LinkedIn Answers is okay, but they would do very well to partner with StackOverflow (or do their own take on the StackExchange platform) for example. Offering tools like TripIt is a good start. They should try and expand their applications to things like expense tracking, etc, while also doing a better job of making the applications visible and useful.