** spoiler alert ** 
 Summary: a catastrophe reduces the Internet to only Skype and Facebook. It takes humanity 5000 years to recover from this nightmare state of affairs, but they learn a valuable lesson and are careful to avoid it happening again. 
 Seveneves includes the "high-tech future space person still inexplicably carries dead-tree books" trope that many sci-fi authors love to include. (Maybe to pander to fellow bibliophiles?) It usually shatters my suspension of disbelief, but Seveneves is the first story I've read that offers a halfway decent excuse!