- curing cancer
- cheap water purification
- vaccines for tropical diseases (the U.S. / European pharma companies have very little incentive to work on them)
- energy-efficient desalination
- energy-efficient computing systems
- efficient solar panels and cheap fuel cells
- easy access to high-quality learning materials (MIT OCW rocks)
and you think of YouTube, Facebook. Do you want to include Twitter, too? For Christ's sake, the "social media" virus has infected a lot of minds here on HN. Let's put things this way: 5,000 people die everyday all over the world of preventable water diseases, and you're talking of social media as a real problem?