The example of GitHub they use is actually telling. Git is decentralized, so why use GitHub? The answer may be surprising: It's because social has not been decentralized. Yes, status.net existed for a while but it was just about publishing short updates. Also, a few years ago several guys from my college raised money to make Diaspora. That didn't fulfill the promise of a decentralized social web either. Bitcoin is de…
Bitcoin, same story -- mass adoption turns out to be dependent on service providers hosting the wallet, and most users are not miners, eroding many of the decentralization benefits.