A social networking service (also social networking site or SNS) is a platform to build social networks or social relations among people who share similar interests, activities, backgrounds or real-life connections. A social network service consists of a representation of each user (often a profile), his or her social links, and a variety of additional services such as career services. Social network sites are web-based services that allow individuals to create a public profile, create a list of users with whom to share connections, and view and cross the connections within the system. Most social network services are web-based and provide means for users to interact over the Internet, such as e-mail and instant messaging. Social network sites are varied and they incorporate new information and communication tools such as mobile connectivity, photo/video/sharing and blogging. Online community services are sometimes considered a social network service, though in a broader sense, social network service usually means an individual-centered service whereas online community services are group-centered. Social networking sites allow users to share ideas, pictures, posts, activities, events, and interests with people in their network.
According to the Oxford Dictionary, a "social network" is a dedicated website or other application that enables users to communicate with each other by posting information, comments, messages, images, etc. The main types of social networking services are those that contain category places (such as former school year or classmates), means to connect with friends (usually with self-description pages), and a recommendation system linked to trust. Popular methods now combine many of these, with American-based services such as Facebook, Google+, LinkedIn, Instagram, Pinterest, Vine, Tumblr, and Twitter widely used worldwide; Wechat, Sina Weibo, and Tencent QQ in China; Nexopia in Canada; Badoo, Bebo, Vkontakte (Russia), Delphi, Draugiem.lv (Latvia), iWiW (Hungary), Nasza-Klasa (Poland), Soup (Austria), Glocals in Switzerland, Skyrock, The Sphere, StudiVZ (Germany), Tagged, Tuenti (mostly in Spain), Myspace, Xanga and XING in parts of Europe; Hi5 in South America and Central America; Mxit in Africa; CarnivalPics based in Nigeria; Cyworld, Mixi, Renren, Friendster, Sina Weibo and Wretch in Asia and the Pacific Islands. Social network services can be split into three types: socializing social network services are primarily for socializing with existing friends (e.g., Facebook); networking social network services are primarily for non-social interpersonal communication (e.g., LinkedIn); and social navigation social network services are primarily for helping users to find specific information or resources (e.g., Goodreads for books)