Did Microsoft overvalue Facebook at $15 billion

Looks like Google pushed MS to do so by engaging in a bid war though Google was uninterested in Facebook. Microsoft acquired 1.6 percent stake valuing Facebook at $15 billion

Estimated revenues from Facebook: $150 million
A $15 billion valuation is 100 times this revenue
Approximate user base: 50 million
Microsoft’s perceived Facebook value per member: $300