You can now add applications in LinkedIn just the way you add Facebook apps.
The initial set of LinkedIn Apps are provided by SlideShare (for uploading Office documents), Box.net (for sharing files), Google Docs (for PowerPoint presentations), Blog Links (for reading blogs) and Amazon Reading List (for sharing books you are reading).
There’s another useful LinkedIn app called "Company Buzz" that is basically a twitter search engine tracking any mention of your employer’s name across the twitter network.
Now when you add this Company Buzz application to your Twitter profile, it’s pre-populated with search topics corresponding to all your ex- and current employer.
You can however add your own topics as well remove existing search terms through the "manage topics" link.
Twitter search inside LinkedIn is different from the default twitter search engine so search operators like filter:links or near:CA will not work but the interesting part is that you can save and bookmark search topics that you frequently scan on twitter.