In the fall of 2009, I sent the manuscript for my book Personal Connections in the Digital Age off to press. I’ve just finished the index for a second edition, which will be published by Polity in mid-2015 (in time for fall classes!). The list of terms I added provides a fun little peek into the last 5 years of digital media and social life. What would you have added? What words would you expect to see in a third edition?
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4chan
Algorithms
Black Twitter
Broadband
Catfish
Cortana
Culture jamming
Cyberbullying
Emojis
FourSquare (also: Swarm)
Grindr
Hashtag
Her
Imgur
Indie Go-Go
Instagram
Kickstarter
Knowyourmeme.com
Locative media
Lolspeak
Micro-celebrity
Pinterest
Polymedia
Reddit
Self-branding
Selfie (selfies)
Sina Weibo
Siri
Slacktivism
Snapchat
Spotify
Tumblr
WhatsApp
Wikipedia
Wordpress.com
Xbox Live
XKCD
Social Media Collective 
Nancy, ORKUT, ORKUT, ORKUT 🙂 It was huge in Brazil and India, and it played such a major role in peoples ways of communication.
Don’t worry, David! The only reason it wasn’t added is that it was already in the index of the 1st edition.
Ah, gotcha. I’m not sure if this is exactly what you are looking for, but how about mentioning social networking sites, like ello, that emerged as a counter-response to Facebook’s policies on privacy and use of user’s data?