Online communities such as Facebook, Twitter, LinkedIn and Google+ have different networking and engagement rules. Facebook is a network of friends and family whereas Twitter is a network of people/things you find interesting and LinkedIn is a network of colleagues that is fast evolving to include closer strangers!
In its earlier days, LinkedIn put a lot of emphasis on only connecting with people you had done business with hence the vast majority of LinkedIn requests came from direct or indirect workmates. According to LinkedIn CEO Jeff Weiner LinkedIn is now a service for connecting talent to companies.
LinkedIn originally was a more closed network to cater for largely people you know from a profession perspective though this seem to be fast evolving to encourage more people to join and do more interacting. Getting more people connecting is essential for LinkedIn to continue growing its user-base and therefore its business. This has seen LinkedIn evolve into a bigger business and talent network that can further careers of individuals and help companies get the best talent.
Individuals and companies looking to further their careers and talent base respectively should hence embrace LinkedIn, the business and talent Network.