LinkedIn is a global professional networking resource that can be effectively used for free. In 2011 it is estimated over half the revenues realized by LinkedIn are from their Recruiting tools. These tools reduce the costs for job postings, reduce the effort to identify quality people for a position, and allow their recruitment to be done quietly. LinkedIn has grown in popularity globally and currently as added 2 new member per second for the past several years with over 220,000,000 members as of January 2013.
To be found on LinkedIn it is essential you have a complete Profile containing ample and appropriate keywords presented in a meaningful and attractive form. A LinkedIn Profile that lacks the needed keywords is a cloak of invisibility on your Profile. Just having a Profile with little or poor content can be a negative reflection on you.
Here are some links to information offered to help you understand the importance of not only being on LinkedIn but of having a high quality, attractive, and key word rich presentation including a number of steps to increase your visibility.
NOTE: LinkedIn does offer various membership levels which include monthly or annual charges. It is not necessary to have a paid account with LinkedIn to receive substantial benefit from their services or data.