Recently someone asked at a business gathering, why would someone purchase the paid version of LinkedIn. I couldn’t give a compelling answer. However, LinkedIn has just announced a couple features that make paying for the service seem plausible. Now if you perform a search on contacts, you can save them to a folder for latter review. Also, you can write notes to yourself about the contacts as well.
http://blog.linkedin.com/2009/10/01/getting-organized-with-linkedins-profile-organizer/