Essentially I believe LinkedIn was designed more so for professional networking. Facebook began as a way to connect with friends in college, and now, Twitter kind of combines professionals and casual social interaction. LinkedIn seems to take another step in the next direction toward completing the professional social media site. It becomes your online resume.
I like this resource a lot from Socialnomics written by Erik Qualman. He gives great ways to separate yourself from millions of other people on LinkedIn.
This particular resource is also effective. It gives many ideas and examples to use for your LinkedIn profile that are not accessible otherwise.
LinkedIn has become effective for employees and employers young and old. Hopefully it will be effective for you as well.