I asked the same thing vmware support a while ago and received the following answer.
Definition of "Site":
means the structure in in a single geographic location in which the datacenter resides. A site that is on the same campus but in a different structure within that campus is considered a separate site
Note: the you can not use licenses all over the world.
1.14 “Territory” means the country or countries in which You have been invoiced; provided, however, that if You have been invoiced within any of the European Economic Area member states, You may deploy the corresponding Software throughout the European Economic Area. - See more at: http://www.vmware.com/download/eula/esxi50_eula.html#sthash.4AadgP9a.dpuf
-> with Global Deployment Rights the licenses can be deployed across different countries
