I always ask younger people their social network of choice just to make sure what the stats say match up with reality.
Almost 9/10 say Instagram is their primary network while Snapchat is used on occasion. Facebook goes unmentioned because it’s just part of everyday life, like reading the newspaper or checking email. Consumption is assumed.
Very few people I talk to say that Twitter is their first choice. However, those who do claim the network to be indispensable. Twitter is their tool for discovery, sharing, and online discourse. Not surprisingly, these people are mostly writers and heavy readers.
Tumblr and Pinterest are always mentioned as ancillary networks that are fun, useful, and niche but not to die for.
Flickr never gets mentioned. And neither does Path, Highlight, nor Secret. It’s not surprising that these are all apps more popular in Silicon Valley than amongst common users. Nerds rarely create waves of mass adoption.
Instagram is killing it. It’s the best way to tell edited and sometimes raw stories about your life. People communicate in pictures. Since Instagram grew up as a mobile app first, every UI and UX aspect of the app is optimized for mobile devices.
Facebook has done a good job in allowing Instagram to operate on its own terms and market itself outside the social networking Goliath. But in a few years Instagram will too be normalized and a new social-sharing phenomenon (probably a more private one) will be the talk of the town. Facebook, too, is covered there with WhatsApp.