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. 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 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.
Early social networking on the World Wide Web began in the form of generalized online communities such as Theglobe.com, Geocities and Tripod.com (all three in mid-1990s). Many of these early communities focused on bringing people together to interact with each other through chat rooms, and encouraged users to share personal information and ideas via personal webpages by providing easy-to-use publishing tools and free or not expensive webspace. In the late 1990s, user profiles became a central feature of social networking sites, allowing users to compile lists of "friends" and search for other users with similar interests. New social networking methods were developed by the end of the 1990s, and many sites began to develop more advanced features for users to find and manage friends. Among them there were such nets as SixDegrees.com, Makeoutclub, Hub Culture Friendster, MySpace and LinkedIn. But the real success was achieved by Facebook, launched in 2004. It was first introduced as a Harvard social networking site, expanding to other universities and eventually, anyone.
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. Popular methods now combine many of these, with American-based services such as Facebook, Google+, LinkedIn, Instagram, Pinterest, Tumblr, Twitter, Russian Vkontakte, Chinese Sina Weibo, etc..
Social networking sites share a variety of technical features that allow individuals to: construct a public/semi-public profile, a list of other users that they share a connection with, and view their list of connections within the system. The most basic of these are visible profiles with a list of "friends" who are also users of the site. A profile is generated from answers to questions, such as age, location, interests, etc. Some sites allow users to upload pictures, add multimedia content or modify the look of the profile.
Web-based social networking services make it possible to connect people who share interests and activities across political, economic, and geographic borders. Companies are using social media as a way to learn about potential employees' personalities and behavior. In numerous situations a candidate who might otherwise have been hired has been rejected due to offensive photos or comments posted to social networks or appearing on a newsfeed. Social networking tools are increasingly the object of scholarly research. Scholars in many fields have begun to investigate the impact of social networking sites, how they may play into issues of identity, privacy, social capital, youth culture, and education.
