LinkedIn is a business and employment-oriented social networking service that operates via websites. it is mainly used for professional networking, including employers posting jobs and job seekers posting their CVs. LinkedIn allows users (workers and employers) to create profiles and “connections” to each other in an online social network which may represent real-world professional relationships. Users can invite anyone (whether a site user or not) to become a connection.
LinkedIn ‘applications’ often refers to external third party applications that interact with LinkedIn’s developer API. However, in some cases it could refer to sanctioned applications featured on a user’s profile page.