What are some good Social Networking sites for the corporate world?

Answer:
LinkedIn is an exclusive networking site, targeting

upper level business users. You can only join LinkedIn by invitation, and the site protects users from being found by the public. LinkedIn differs from many other networking sites by its minimalist approach. You won't find forums on LinkedIn, and there are no specific job listings. Instead, there are statistics about the network that you are in, and request pages that can be used to approach a contact about jobs or other opportunities.

Assuming that influential people will be discriminating about passing along contacts and references, LinkedIn requires other people to approve requests to approach potential employers with resumes, or other requests.

Users can post endorsements of other members on their profiles, making those members more attractive to potential contacts. LinkedIn is elite , which may be the key to its success.