LinkedIn is a business-oriented networking site founded in December 2002 and launched in May 2003 (comparable to a social networking site), mainly used for professional networking. As of December 2007, it had more than 17 million registered users, spanning 150 industries and more than 400 economic regions (as classified by the service).
LinkedIn's CEO is Dan Nye, while former CEO and LinkedIn founder Reid Hoffman, previously an executive vice president of PayPal, remains as President of Product and Chairman of the Board. LinkedIn is located in Mountain View, California, and funded by Greylock, Sequoia Capital, Bessemer Venture Partners, and the European Founders Fund. LinkedIn reached profitability in March 2006.
LinkedIn.com is a private firm operating an internet web portal to foster the development of social networking for professional development and career enhancement in the business community. As of December 2007, it had approximately 3.2 million visitors per month and an annual growth rate in visitors of about 485%.
The 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 site 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, the connections of each of their connections (termed second degree connections) and also the connections of second degree connections (termed third degree connections). This can be used to gain an introduction to someone you wish to know through a mutual, trusted contact.
It can then be used to find jobs, people and business opportunities recommended by someone in one's 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 preexisting relationship, or the intervention of a contact of theirs) is intended to build trust among the service's users. LinkedIn participates in EU's International Safe Harbor Privacy Principles.
The feature LinkedIn Answers, similar to Google Answers or Yahoo! Answers, allows users to ask questions for the community to answer. This feature is free and the main differences from the two previously mentioned services are that questions are potentially more business-oriented, and the identity of the people asking and answering questions is known.
Model of the domain
The diagram on the right, expressed using the UML standard notation for class diagrams, represents a subset of the information managed by LinkedIn. It gives a global overview of the core entities, relations and fields stored by the system.
For instance, the diagram shows what fields are associated with the notion of Position, RecommendationRequest, Education and so on (see the corresponding boxes representing classes).
Note that this is only a conceptual class diagram; it describes the concepts rather than the implementation and the details of the database.
Non-members can check whether or not a person is a member. As of August 2007, this feature can be disabled.
There is no automated way to remove oneself from LinkedIn. The official method is to file a customer support ticket.
Sites with comparable features
There are several websites that offer online business networking, including ryze, XING, Plaxo, Yahoo! Kickstart and, increasingly Facebook. LinkedIn answers is comparable to Yahoo! Answers. Various websites such as CareerBuilder.com, Yahoo! HotJobs, GlobalPitch.com and Monster.com have job search functions. Many websites have reputation systems and online social networking.
Plaxo is an online address book service founded by Napster co-founder Sean Parker, Minh Nguyen, and two Stanford engineering students, Todd Masonis and Cameron Ring. Plaxo, based in Mountain View, California, is currently privately held and supported by venture capital. In October 2006, the website reported 15 million users.
Plaxo provides automatic updating of contact information. Users and their contacts store their information on Plaxo's servers. When this information is edited by the user, the changes appear in the address books of all those who listed the account changer in their own books. Once contacts are stored in the central location, it is possible to list connections between contacts and access the address book from anywhere.
A Plaxo plug-in supports major address books including Outlook/Outlook Express, Mozilla Thunderbird, and Mac OS X's Address Book, though other ones can be supported through an application programming interface. Additionally, Plaxo can also be maintained through an online version.
Plaxo received criticism from technology journalist David Coursey, who was upset about receiving a number of requests from Plaxo users to update their contact information, and who wondered how the company was planning to make money from a free service that collects personal contact and network information. However after "changes at Plaxo and discussions with the company's remaining co-founders", Coursey reversed his stance. Plaxo also responded to these issues in a section of their website.