@Larry: My impression is the strategies are diverse.
Facebook is fully transparent and open to work with all comers. Microsoft is somewhat open about what its doing on its own. Amazon shares a some info with EC2 end users about what sorts of servers they can buy time on, and Google just gives occational peeks into what its doing.
The datacenter guys (Facebook, Google, Microsoft, Amazon, etc.) actually seem to be cooperating in this area rather than competing. Most of the advances in datacenter design seem to be being shared relatively openly rather than being held as proprietary. In a way that makes sense, since open standards will drive down the cost for their equipment and between these few names they are becoming a significant part of the market.