how many of the unicorns out of SV are actually viable businesses that will gain genuine traction 10 years from now? I suspect not a whole lot
Kayak, Facebook, Twitter, LinkedIn, Bloom Energy and Integra Telecom (Electric Lightwave) are still doing well, Groupon and Zynga are significantly diminished and Living Social, Gilt Group and Better Place are dead.
So the answer appears to be 50/50 and social commerce was a huge fad.