This morning, professional social network LinkedIn announced that it is opening up its API for developers to build applications around the platform. While LinkedIn has partnered with Twitter, Microsoft , IBM, Research In Motion and others, this will be the first time startups can tap into the platform. While LinkedIn is releasing 11 different APIs, they fall into three distinct categories. First, developers will be able to let users easily access their information, profiles, connections and messages via oAuth login. The second functionality is to give users the ability to make actionable decisions about information, but letting them message their LinkedIn contacts, post updates, accept contacts and more. And the third piece of the puzzle is search. So developers will now be able to embed LinkedIn search in other applications. Although the API is now available for all, LinkedIn has already partnered with a select group of developers. Here are a few examples of their integrations.