Imagine...

[Nurvingiel]

One night, unbenownst to you, the craft of an advanced alien race hovered outside your window. As you slept peacefully, the aliens conducted an experiment that went horribly wrong. They intended to copy your brain onto their database for further study. But due to a malfunction in the scanner and an anomaly in the hyperdrive, your brainwaves were copied into every human being in the world.
Ashamed at their failure, the aliens left discreetly. No human had any idea what happened. After the experiment, everyone on Earth (except you), felt a little different. Their memories are the same, but they now hold the exact same values you do.
The only differing factor between one person and the next is their past experiences. Imagine... that everyone on Earth thinks like you!

What are the benefits? The reprecussions? What are the immediate and long-term effects of the change? How are governments and cultures changed? What aspects remain the same? It all depends on what you value.