This is a key insight from Nathan Schneider.
We should also ask ourselves "How do we make Google's hardware, software and services more Accountable." (and also find a metric that describes this...)
We should care less about whether something is centralized or decentralized than whether it is accountable. An accountable system is responsive to both the common good for participants and the needs of minorities; it sets consistent rules and can change them when they don’t meet users’ needs.