Social media often feeds into the discovery of new content such as news stories, and “discovery” is a search activity. Social media can also help build links that in turn support into SEO efforts. Many people also perform searches at social media sites to find social media content. Social connections may also impact the relevancy of some search results, either within a social media network or at a ‘mainstream’ search engine.
Social media may have been influenced by the 1840s introduction of the telegraph in the US, which connected the country.[10] ARPANET, which first came online in 1967, had by the late 1970s developed a rich cultural exchange of non-government/business ideas and communication, as clearly evidenced by ARPANET#Rules and etiquette's "A 1982 handbook on computing at MIT's AI Lab stated regarding network etiquette," and fully met the current definition of the term "social media" found in this article. The PLATO system launched in 1960, which was developed at the University of Illinois and subsequently commercially marketed by Control Data Corporation, offered early forms of social media with 1973-era innovations such as Notes, PLATO's message-forum application; TERM-talk, its instant-messaging feature; Talkomatic, perhaps the first online chat room; News Report, a crowd-sourced online newspaper and blog; and Access Lists, enabling the owner of a notesfile or other application to limit access to a certain set of users, for example, only friends, classmates, or co-workers. Tom Truscott and Jim Ellis conceived the idea of Usenet in 1979 at the University of North Carolina at Chapel Hill and Duke University, and it was established in 1980.

Tumblr is one of the most difficult to use social networking platforms, but it’s also one of the most interesting sites. The platform allows several different post formats, including quote posts, chat posts, video and photo posts as well as audio posts, so you are never limited in the type of content that you can share. Like Twitter, reblogging, which is more like retweeting, is quick and easy. The social networking website was founded by David Karp in February 2007 and currently hosts more than 200 million blogs.

First of all, thanks for sharing this list. It’s really useful, but it would be great to supplement it with some kind of statistics regarding the audience who is using each of these social networks. This statistics could be valuable for different kind of marketers, bloggers or business owners because with such statistics it would be possible to plan a strategy for business in different niches, like e-commerce, paper help online, any kind of services, or use it for the purpose of self-promotions for bloggers/website owners.
Observers have noted a range of positive and negative impacts of social media use. Social media can help to improve an individual's sense of connectedness with real or online communities, and can be an effective communication (or marketing) tool for corporations, entrepreneurs, nonprofit organizations, advocacy groups, political parties, and governments. At the same time, concerns have been raised about possible links between heavy social media use and depression, and even the issues of cyberbullying, online harassment and "trolling". Currently, about half of young adults have been cyberbullied, and of those, 20% said that they have been cyberbullied regularly.[7] Another survey in the U.S. applied the Precaution Process Adoption Model to cyberbullying on Facebook among 7th grade students. According to this study, 69% of 7th grade students claim to have experienced cyberbullying, and they also said that it was worse than face-to-face bullying.[8] Both the bully and the victim are negatively affected, and the intensity, duration, and frequency of bullying are the three aspects that increase the negative effects on both of them.[9]