LinkedIn

LinkedIn is a business oriented social networking site, mainly used for professional networking. As of January 2007, it had more than 9 million registered users, spanning 150 industries and more than 400 economic regions (as classified by the service).

The main purpose of the site is to allow registered users to maintain a list of contact details of people they know and trust in business. The people in the list are called Connections. Users can invite anyone (whether a LinkedIn user or not) to become a connection.

This list of connections can then be used in a number of ways:

• A contact network is built up consisting of their direct connections, each of their connections connections (called 2nd degree connections) and also the connections of 2nd degree connections (called 3rd degree connections). This can be used, for example, to gain an introduction to some-one you wish to know through a mutual, trusted contact.

• It can then be used to find jobs, people and business opportunities recommended by anyone in your contact network.

• Employers can list jobs and search for potential candidates.

• Job seekers can review the profile of hiring managers and discover which of their existing contacts can introduce them.

The "gated-access approach" (where contact with any professional requires either a pre-existing relationship or the intervention of a contact of theirs) is intended to build trust among the service's users.