Stephen Babka: History of Social Media timeline

Six Degrees is considered the first social media site. It was founded by Andrew Weinreich and featured many commonplace features of social media sites, such as profiles, friends list, and your school affiliation. It was deactivated in 2001
McFadden, Christopher. "A Chronological History of Social Media." 16 October 2018. https://interestingengineering.com/a-chronological-history-of-social-media

Friendster came out in 2002, and had many of the same features as Six Degrees, in addition to allowing users to upload photos/videos, send messages, and leave comments on other people's profiles.
Terrell, Keith. "The History of Social Media: Social Networking Evolution!" 16 June 2015. https://historycooperative.org/the-history-of-social-media/

LinkedIn came out in 2003 and gave users the ability to post their resumes and network with people in their professional field, and is today one of the largest and most important social media sites, today totaling over 500 million users.
Ahmad, Irfan. "The History of Social Media." 27 April 2018. https://www.socialmediatoday.com/news/the-history-of-social-media-infographic-1/522285/

Also founded in 2003, MySpace started as a file storage platform, but transitioned to a social networking site, and was the largest social media site from 2005 to 2008.
Terell, Keith. "The History of Social Media: Social Networking Evolution!" 16 June 2015. https://historycooperative.org/the-history-of-social-media/

Facebook is launched by Mark Zuckerberg in 2004 initially for college students, before becoming accessible by everyone worldwide. It is now the largest and most important social networking site in the world
Ahmad, Irfan. "The History of Social Media." 27 April 2018. https://www.socialmediatoday.com/news/the-history-of-social-media-infographic-1/522285/

YouTube allows users to view and upload videos and is the second most-visited site in the world, behind Google (which owns YouTube). The accessibility of the platform allows many people to reach heights of fame previously thought to be reserved for typical celebrities
McFadden, Christopher. "A Chronological History of Social Media." 16 October 2018. https://interestingengineering.com/a-chronological-history-of-social-media

Reddit was created by Alexis Ohanian and Steve Huffman and serves as a "front page for the internet" allowing users to upvote posts in their genre that are then displayed on the Reddit homepage, allowing users to save time having to browse a lot of different sites
Lagorio-Chafkin, Christine. "Is Reddit the Most Influential Site on the Internet?" 7 February 2019. https://knowledge.wharton.upenn.edu/article/history-of-reddit/

Launched in 2006, Twitter offers something unique compared to other social media sites: an ability to interact with (and get replies from) your favorite celebrities
McFadden, Christopher. "A Chronological History of Social Media." 16 October 2018. https://interestingengineering.com/a-chronological-history-of-social-media

Instagram was launched in 2010 and was notable for being a mobile exclusive app focused on photos and videos, making it more attractive to a younger crowd
Terrell, Keith. "The History of Social Media: Social Networking Evolution!" 16 June 2015. https://historycooperative.org/the-history-of-social-media/

Snapchat, founded in 2011, is probably one of the most important sites for the modern generation. Getting someone's "snap" is the modern-day equivalent of getting a phone number. The most notable characteristic of Snapchat is that it allows users to send messages that disappear shortly after being viewed.
Terrell, Keith. "The History of Social Media: Social Networking Evolution!" 16 June 2015. https://historycooperative.org/the-history-of-social-media/