Additionally there is http://www.opencompute.org/ http://www.opencompute.org/, which was initially created by facebook. I also think arduino may have some open

Additionally there is http://www.opencompute.org/ http://www.opencompute.org/, which was initially created by facebook. I also think arduino may have some open hardware as well. As for why they're rarer? Hardware is expensive, has a smaller margin of error and has had good vendors for a long time. Few companies build their own hardware, and many that do consider it a competitive advantage (Google certainly does)