With over 900 million estimated unique monthly users, Facebook tops the list of the most popular online social networks, as of October 2015. Twitter comes in at number two with 310 million unique monthly users, while LinkedIn, a professional networking platform, ranks at number three with 255 million unique monthly users. Pinterest gets the number four spot with 250 million, Google Plus comes in at number five with 120 million and Tumblr ranks in sixth with 110 million.
Founded in 2004 by chairman and CEO Mark Zuckerberg, Facebook offers a wide array of connectivity tools that let users share photos, news and other information with friends and family members around the world. Users set up profiles containing identifying information and then share links, photos, thoughts and more on their personal timelines. Apps for Android and Apple smartphones and tablets make it simple for users to keep in touch with each other while they're on the go.
Launched in 2006, Twitter offers users the ability to send 140-character text messages called "tweets." These short and to-the-point messages span the gamut from information sharing between friends to companies announcing news or sales. Users log on to the Twitter website or access the platform using apps for Android or Apple smartphones or tablets.