Facebook is a corporation and online social networking service headquartered in Menlo Park, California, in the United States. Its website was launched on February 4, 2004, by Mark Zuckerberg with his Harvard College roommates and fellow students Eduardo Saverin, Andrew McCollum, Dustin Moskovitz and Chris Hughes.

Twitter was created in March 2006 by Jack Dorsey, Evan Williams, Biz Stone, and Noah Glass and launched in July 2006. The service rapidly gained worldwide popularity, with more than 100 million users posting 340 million tweets a day in 2012.

Google+ launched on December 15, 2011. Features included the ability to post photos and status updates to the stream or interest based communities, group different types of relationships (rather than simply "friends") into Circles, a multi-person instant messaging, text and video chat called Hangouts, events, location tagging, and the ability to edit and upload photos to private cloud-based albums.

Launched on October 6, 2010, Instagram is an online mobile photo-sharing, video-sharing, and social networking service that enables its users to take pictures and videos, and share them either publicly or privately on the app, as well as through a variety of other social networking platforms.

Pinterest was first conceptualized in December 2009 by cofounders Ben Silbermann, Evan Sharp and Paul Sciarra. The first prototype was launched in March 2010 and made available to a small group of colleagues and family members.

It had been Chris's first time using Tumblr. "My understanding was that it was an image-sharing platform," he says. "I was vaguely aware that it was hipsterish." Tumblr launched in February 19, 2007, with the tagline "Blogging made easy".

Snapchat first launched in July 2011 under the name Picaboo in Spiegel's father's living room, though the application was later renamed and relaunched under the name Snapchat.

Originally incubated inside Hatch Labs, the app was launched on September 12, 2012, and by 2014 it was registering about one billion “swipes” per day. Tinder was among the first “swiping apps”, where the user uses a swiping motion to choose between the photos of other users: swiping right for potentially good matches and swiping left on a photo to move to the next one.

Ello is an online social networking service created by Paul Budnitz and Todd Berger in March 2014. It was created as an ad-free alternative to existing social networks, such as Facebook and Twitter. It is currently in beta.

LinkedIn's founders are Reid Hoffman, Allen Blue, Konstantin Guericke, Eric Ly and Jean-Luc Vaillant. LinkedIn started out in the living room of co-founder Reid Hoffman in 2002. The site officially launched on May 5, 2003.