LinkedIn has a number of useful applications that will let you maximize the effect of your professional profile.
LinkedIn Today
LinkedIn Today compiles content from the internet and puts them in one handy location. This is a great place to find industry related articles and determine what the hot topics in your industry are. The first time you visit the application it will suggest industries it feels are relevant to you. Pick which industries you find the most interesting or relevant and it will pull start pulling the relevant articles for you to see. Most articles are pulled from Twitter, so they follow the same 140 character limit for the headlines. The articles which have been shared the most and the one with the most comments are put near the top of the news to make it easier to find the hot topics.
WordPress
A blog is an important part of your personal brand, this is one of the best ways to showcase your knowledge and work and broadcast your own unique styling. A blog can be used to voice your opinions in an informal method or to offer up instructions in your area of expertise. Even a weak blog post has a lot more relevance than a strong social networking post, because a blog has a longer lifespan and is on the internet forever. WordPress has an application that will embed your blog in to your profile. This allows anyone visiting your LinkedIn profile to see what you have been writing about.
SlideShare
This is a popular application that allows you to put a Powerpoint presentation or PDF in to your LinkedIn profile. This is a fantastic way to show off presentations or training sessions you have given. You can also create a presentation that shows your expertise by detailing your specific skills.
Google Presentations
This is very similar to SlideShare however it has the additional capability of uploading video into your profile. This is excellent to show any demo videos or talks you may have given.
There are many other useful applications such as Portfolio Display, Events, Amazon Reading list and MyTravel. All of the applications have their strengths and can be useful to enhance your profile.